Bug 565388 - No paint for invisible docshell. r=tnikkel

content/base/src/nsDocument.cpp

@@ -3478,6 +3478,11 @@ nsDocument::doCreateShell(nsPresContext* aContext,
   // Note: we don't hold a ref to the shell (it holds a ref to us)
   mPresShell = shell;
 
+  // Make sure to never paint if we belong to an invisible DocShell.
+  nsCOMPtr<nsIDocShell> docShell = do_QueryReferent(mDocumentContainer);
+  if (docShell && docShell->IsInvisible())
+    shell->SetNeverPainting(true);
+
   mExternalResourceMap.ShowViewers();
 
   MaybeRescheduleAnimationFrameNotifications();

docshell/base/nsDocShell.cpp

@@ -765,6 +765,7 @@ nsDocShell::nsDocShell():
     mInEnsureScriptEnv(false),
 #endif
     mAffectPrivateSessionLifetime(true),
+    mInvisible(false),
     mDefaultLoadFlags(nsIRequest::LOAD_NORMAL),
     mFrameType(eFrameTypeRegular),
     mOwnOrContainingAppId(nsIScriptSecurityManager::UNKNOWN_APP_ID),
@@ -12801,3 +12802,15 @@ nsDocShell::HasUnloadedParent()
     }
     return false;
 }
+
+bool
+nsDocShell::IsInvisible()
+{
+    return mInvisible;
+}
+
+void
+nsDocShell::SetInvisible(bool aInvisible)
+{
+    mInvisible = aInvisible;
+}

docshell/base/nsDocShell.h

@@ -846,6 +846,7 @@ protected:
     bool                       mInEnsureScriptEnv;
 #endif
     bool                       mAffectPrivateSessionLifetime;
+    bool                       mInvisible;
     uint64_t                   mHistoryID;
     uint32_t                   mDefaultLoadFlags;
 

docshell/base/nsIDocShell.idl

@@ -43,7 +43,7 @@ interface nsIReflowObserver;
 
 typedef unsigned long nsLoadFlags;
 
-[scriptable, builtinclass, uuid(4ca172c3-67bf-4e6d-89a3-cbfb929c370d)]
+[scriptable, builtinclass, uuid(c0bb3b19-5448-4f4d-9366-cbcd4d7cdb96)]
 interface nsIDocShell : nsIDocShellTreeItem
 {
   /**
@@ -922,4 +922,12 @@ interface nsIDocShell : nsIDocShellTreeItem
     */
   boolean isCommandEnabled(in string command);
   void doCommand(in string command);
+
+  /**
+   * Invisible DocShell are dummy construct to simulate DOM windows
+   * without any actual visual representation. They have to be marked
+   * at construction time, to avoid any painting activity.
+   */
+  [noscript, notxpcom] bool IsInvisible();
+  [noscript, notxpcom] void SetInvisible(in bool aIsInvisibleDochsell);
 };

layout/base/nsIPresShell.h

@@ -126,10 +126,10 @@ typedef struct CapturingContentInfo {
 } CapturingContentInfo;
 
 
-// d39cd4ce-6b38-4793-8c1a-00985c56d931
+// f5b542a9-eaf0-4560-a656-37a9d379864c
 #define NS_IPRESSHELL_IID \
-{ 0xd39cd4ce, 0x6b38, 0x4793, \
-  { 0x8c, 0x1a, 0x00, 0x98, 0x5c, 0x56, 0xd9, 0x31 } }
+{ 0xf5b542a9, 0xeaf0, 0x4560, \
+  { 0x37, 0xa9, 0xd3, 0x79, 0x86, 0x4c } }
 
 // debug VerifyReflow flags
 #define VERIFY_REFLOW_ON                    0x01
@@ -1467,6 +1467,17 @@ public:
     mReflowOnZoomPending = false;
   }
 
+  /**
+   * Documents belonging to an invisible DocShell must not be painted ever.
+   */
+  bool IsNeverPainting() {
+    return mIsNeverPainting;
+  }
+
+  void SetNeverPainting(bool aNeverPainting) {
+    mIsNeverPainting = aNeverPainting;
+  }
+
 protected:
   friend class nsRefreshDriver;
 
@@ -1588,6 +1599,11 @@ protected:
   // The maximum width of a line box. Text on a single line that exceeds this
   // width will be wrapped. A value of 0 indicates that no limit is enforced.
   nscoord mMaxLineBoxWidth;
+  
+  // If a document belongs to an invisible DocShell, this flag must be set
+  // to true, so we can avoid any paint calls for widget related to this
+  // presshell.
+  bool mIsNeverPainting;
 };
 
 #endif /* nsIPresShell_h___ */

layout/base/nsPresShell.cpp

@@ -7424,7 +7424,7 @@ PresShell::GetCurrentItemAndPositionForElement(nsIDOMElement *aCurrentEl,
 bool
 PresShell::ShouldIgnoreInvalidation()
 {
-  return mPaintingSuppressed || !mIsActive;
+  return mPaintingSuppressed || !mIsActive || mIsNeverPainting;
 }
 
 void

view/src/nsViewManager.cpp

@@ -295,6 +295,10 @@ void nsViewManager::Refresh(nsView *aView, const nsIntRegion& aRegion)
 {
   NS_ASSERTION(aView->GetViewManager() == this, "wrong view manager");
 
+  if (mPresShell && mPresShell->IsNeverPainting()) {
+    return;
+  }
+
   // damageRegion is the damaged area, in twips, relative to the view origin
   nsRegion damageRegion = aRegion.ToAppUnits(AppUnitsPerDevPixel());
   // move region from widget coordinates into view coordinates
@@ -370,6 +374,10 @@ void nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
     return;
   }
 
+  if (mPresShell && mPresShell->IsNeverPainting()) {
+    return;
+  }
+
   if (aView->HasWidget()) {
     aView->ResetWidgetBounds(false, true);
   }
@@ -415,6 +423,7 @@ void nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
         printf("---- PAINT END ----\n");
       }
 #endif
+
       aView->SetForcedRepaint(false);
       SetPainting(false);
       FlushDirtyRegionToWidget(aView);

xpfe/appshell/src/nsAppShellService.cpp

@@ -395,6 +395,9 @@ nsAppShellService::CreateWindowlessBrowser(bool aIsChrome, nsIWebNavigation **aR
 
   nsISupports *isstub = NS_ISUPPORTS_CAST(nsIWebBrowserChrome2*, stub);
   nsRefPtr<nsIWebNavigation> result = new WindowlessBrowserStub(browser, isstub);
+  nsCOMPtr<nsIDocShell> docshell = do_GetInterface(result);
+  docshell->SetInvisible(true);
+
   result.forget(aResult);
   return NS_OK;
 }