Bug 343515 - need API for tabbrowsers to tell docshells they're visible/hidden.r=gavin,sr=bz,a=blocker

browser/base/content/tabbrowser.xml

@@ -737,8 +737,10 @@
             this._lastRelatedTab = null;
 
             var oldBrowser = this.mCurrentBrowser;
-            if (oldBrowser)
+            if (oldBrowser) {
               oldBrowser.setAttribute("type", "content-targetable");
+              oldBrowser.docShell.isActive = false;
+            }
 
             var updatePageReport = false;
             if (!oldBrowser ||
@@ -747,6 +749,7 @@
               updatePageReport = true;
 
             newBrowser.setAttribute("type", "content-primary");
+            newBrowser.docShell.isActive = true;
             this.mCurrentBrowser = newBrowser;
             this.mCurrentTab = this.selectedTab;
 
@@ -1189,6 +1192,10 @@
                 flags |= Ci.nsIWebNavigation.LOAD_FLAGS_FROM_EXTERNAL;
               try {
                 b.loadURIWithFlags(aURI, flags, aReferrerURI, aCharset, aPostData);
+
+                // We start our browsers out as inactive, and then maintain
+                // activeness in the tab switcher.
+                b.docShell.isActive = false;
               }
               catch (ex) { }
             }

docshell/base/nsDocShell.cpp

@@ -703,6 +703,7 @@ nsDocShell::nsDocShell():
     mAllowAuth(PR_TRUE),
     mAllowKeywordFixup(PR_FALSE),
     mIsOffScreenBrowser(PR_FALSE),
+    mIsActive(PR_TRUE),
     mFiredUnloadEvent(PR_FALSE),
     mEODForCurrentDocument(PR_FALSE),
     mURIResultedInDocument(PR_FALSE),
@@ -2496,6 +2497,10 @@ nsDocShell::SetDocLoaderParent(nsDocLoader * aParent)
         {
             SetAllowImages(value);
         }
+        if (NS_SUCCEEDED(parentAsDocShell->GetIsActive(&value)))
+        {
+            SetIsActive(value);
+        }
         if (NS_FAILED(parentAsDocShell->GetAllowDNSPrefetch(&value))) {
             value = PR_FALSE;
         }
@@ -4618,6 +4623,40 @@ nsDocShell::GetIsOffScreenBrowser(PRBool *aIsOffScreen)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::SetIsActive(PRBool aIsActive)
+{
+  // We disallow setting active on chrome docshells.
+  if (mItemType == nsIDocShellTreeItem::typeChrome)
+    return NS_ERROR_INVALID_ARG;
+
+  // Keep track ourselves.
+  mIsActive = aIsActive;
+
+  // Tell the PresShell about it.
+  nsCOMPtr<nsIPresShell> pshell;
+  GetPresShell(getter_AddRefs(pshell));
+  if (pshell)
+    pshell->SetIsActive(aIsActive);
+
+  // Recursively tell all of our children
+  PRInt32 n = mChildList.Count();
+  for (PRInt32 i = 0; i < n; ++i) {
+      nsCOMPtr<nsIDocShell> docshell = do_QueryInterface(ChildAt(i));
+      if (docshell)
+        docshell->SetIsActive(aIsActive);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShell::GetIsActive(PRBool *aIsActive)
+{
+  *aIsActive = mIsActive;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDocShell::SetVisibility(PRBool aVisibility)
 {
@@ -6909,7 +6948,10 @@ nsDocShell::RestoreFromHistory()
 
         PRBool allowDNSPrefetch;
         childShell->GetAllowDNSPrefetch(&allowDNSPrefetch);
-        
+
+        // this.AddChild(child) calls child.SetDocLoaderParent(this), meaning
+        // that the child inherits our state. Among other things, this means
+        // that the child inherits our mIsActive, which is what we want.
         AddChild(childItem);
 
         childShell->SetAllowPlugins(allowPlugins);

docshell/base/nsDocShell.h

@@ -787,6 +787,7 @@ protected:
     PRPackedBool               mAllowAuth;
     PRPackedBool               mAllowKeywordFixup;
     PRPackedBool               mIsOffScreenBrowser;
+    PRPackedBool               mIsActive;
 
     // This boolean is set to true right before we fire pagehide and generally
     // unset when we embed a new content viewer.  While it's true no navigation

docshell/base/nsIDocShell.idl

@@ -71,7 +71,7 @@ interface nsIPrincipal;
 interface nsIWebBrowserPrint;
 interface nsIVariant;
 
-[scriptable, uuid(8ac6b880-776a-44d4-b271-a7e64ae3debd)]
+[scriptable, uuid(bf6db598-3833-400b-9e53-ec220cb2496c)]
 interface nsIDocShell : nsISupports
 {
   /**
@@ -521,4 +521,11 @@ interface nsIDocShell : nsISupports
    * current docshell.
    */
   readonly attribute boolean canExecuteScripts;
+
+  /**
+   * Sets whether a docshell is active. An active docshell is one that is
+   * visible, and thus is not a good candidate for certain optimizations
+   * like image frame discarding. Docshells are active unless told otherwise.
+   */
+  attribute boolean isActive;
 };

embedding/browser/webBrowser/nsIWebBrowser.idl

@@ -52,7 +52,7 @@ interface nsIWeakReference;
  * to register any listeners. The interface may also be used at runtime
  * to obtain the content DOM window and from that the rest of the DOM.
  */
-[scriptable, uuid(69E5DF00-7B8B-11d3-AF61-00A024FFC08C)]
+[scriptable, uuid(33e9d001-caab-4ba9-8961-54902f197202)]
 interface nsIWebBrowser : nsISupports
 {
     /**
@@ -165,4 +165,15 @@ interface nsIWebBrowser : nsISupports
      * @see nsIDOMWindow
      */
     readonly attribute nsIDOMWindow contentDOMWindow;
+
+    /**
+     * Whether this web browser is active. Active means that it's visible
+     * enough that we want to avoid certain optimizations like discarding
+     * decoded image data and throttling the refresh driver. In Firefox,
+     * this corresponds to the visible tab.
+     *
+     * Defaults to true. For optimal performance, set it to false when
+     * appropriate.
+     */
+    attribute boolean isActive;
 };

embedding/browser/webBrowser/nsWebBrowser.cpp

@@ -108,6 +108,7 @@ nsWebBrowser::nsWebBrowser() : mDocShellTreeOwner(nsnull),
    mContentType(typeContentWrapper),
    mActivating(PR_FALSE),
    mShouldEnableHistory(PR_TRUE),
+   mIsActive(PR_TRUE),
    mParentNativeWindow(nsnull),
    mProgressListener(nsnull),
    mBackgroundColor(0),
@@ -419,6 +420,23 @@ NS_IMETHODIMP nsWebBrowser::GetContentDOMWindow(nsIDOMWindow **_retval)
     return rv;
 }
 
+NS_IMETHODIMP nsWebBrowser::GetIsActive(PRBool *rv)
+{
+  *rv = mIsActive;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsWebBrowser::SetIsActive(PRBool aIsActive)
+{
+  // Set our copy of the value
+  mIsActive = aIsActive;
+
+  // If we have a docshell, pass on the request
+  if (mDocShell)
+    return mDocShell->SetIsActive(aIsActive);
+  return NS_OK;
+}
+
 //*****************************************************************************
 // nsWebBrowser::nsIDocShellTreeItem
 //*****************************************************************************   
@@ -1631,6 +1649,12 @@ NS_IMETHODIMP nsWebBrowser::SetDocShell(nsIDocShell* aDocShell)
          // By default, do not allow DNS prefetch, so we don't break our frozen
          // API.  Embeddors who decide to enable it should do so manually.
          mDocShell->SetAllowDNSPrefetch(PR_FALSE);
+
+         // It's possible to call setIsActive() on us before we have a docshell.
+         // If we're getting a docshell now, pass along our desired value. The
+         // default here (true) matches the default of the docshell, so this is
+         // a no-op unless setIsActive(false) has been called on us.
+         mDocShell->SetIsActive(mIsActive);
      }
      else
      {

embedding/browser/webBrowser/nsWebBrowser.h

@@ -169,6 +169,7 @@ protected:
    PRUint32                   mContentType;
    PRPackedBool               mActivating;
    PRPackedBool               mShouldEnableHistory;
+   PRPackedBool               mIsActive;
    nativeWindow               mParentNativeWindow;
    nsIWebProgressListener    *mProgressListener;
    nsCOMPtr<nsIWebProgress>      mWebProgress;

layout/base/nsIPresShell.h

@@ -954,6 +954,16 @@ public:
     return mObservesMutationsForPrint;
   }
 
+  void SetIsActive(PRBool aIsActive)
+  {
+    mIsActive = aIsActive;
+  }
+
+  PRBool IsActive()
+  {
+    return mIsActive;
+  }
+
   // mouse capturing
 
   static CapturingContentInfo gCaptureInfo;
@@ -1083,6 +1093,7 @@ protected:
   PRPackedBool              mIsReflowing;
   PRPackedBool              mPaintingSuppressed;  // For all documents we initially lock down painting.
   PRPackedBool              mIsThemeSupportDisabled;  // Whether or not form controls should use nsITheme in this shell.
+  PRPackedBool              mIsActive;
 
 #ifdef ACCESSIBILITY
   /**

layout/base/nsPresShell.cpp

@@ -1362,6 +1362,9 @@ public:
   static PRInt64 SizeOfBidiMemoryReporter(void *) {
     return EstimateShellsMemory(LiveShellBidiSizeEnumerator);
   }
+
+protected:
+  void QueryIsActive();
 };
 
 class nsAutoCauseReflowNotifier
@@ -1595,6 +1598,7 @@ PresShell::PresShell()
 #endif
   mSelectionFlags = nsISelectionDisplay::DISPLAY_TEXT | nsISelectionDisplay::DISPLAY_IMAGES;
   mIsThemeSupportDisabled = PR_FALSE;
+  mIsActive = PR_TRUE;
 #ifdef DEBUG
   mPresArenaAllocCount = 0;
 #endif
@@ -1801,6 +1805,9 @@ PresShell::Init(nsIDocument* aDocument,
   }
 #endif // MOZ_SMIL
 
+  // Get our activeness from the docShell.
+  QueryIsActive();
+
   return NS_OK;
 }
 
@@ -7306,6 +7313,10 @@ PresShell::Thaw()
     mDocument->EnumerateSubDocuments(ThawSubDocument, nsnull);
 
   UnsuppressPainting();
+
+  // Get the activeness of our presshell, as this might have changed
+  // while we were in the bfcache
+  QueryIsActive();
 }
 
 void
@@ -8943,3 +8954,16 @@ void nsIPresShell::ReleaseStatics()
   delete sLiveShells;
   sLiveShells = nsnull;
 }
+
+// Asks our docshell whether we're active.
+void PresShell::QueryIsActive()
+{
+  nsCOMPtr<nsISupports> container = mPresContext->GetContainer();
+  nsCOMPtr<nsIDocShell> docshell(do_QueryInterface(container));
+  if (docshell) {
+    PRBool isActive;
+    nsresult rv = docshell->GetIsActive(&isActive);
+    if (NS_SUCCEEDED(rv))
+      SetIsActive(isActive);
+  }
+}