Avoid dropped control-key events by making LastModifierState global. b=463802 r=masayuki,josh sr=roc

widget/src/cocoa/nsAppShell.mm

@@ -62,6 +62,7 @@
 // defined in nsChildView.mm
 extern nsIRollupListener * gRollupListener;
 extern nsIWidget         * gRollupWidget;
+extern PRUint32          gLastModifierState;
 
 // defined in nsCocoaWindow.mm
 extern PRInt32             gXULModalLevel;
@@ -816,6 +817,10 @@ nsAppShell::AfterProcessNextEvent(nsIThreadInternal *aThread,
                                              selector:@selector(applicationWillTerminate:)
                                                  name:NSApplicationWillTerminateNotification
                                                object:NSApp];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(applicationDidBecomeActive:)
+                                                 name:NSApplicationDidBecomeActiveNotification
+                                               object:NSApp];
     [[NSDistributedNotificationCenter defaultCenter] addObserver:self
                                                         selector:@selector(beginMenuTracking:)
                                                             name:@"com.apple.HIToolbox.beginMenuTrackingNotification"
@@ -850,6 +855,25 @@ nsAppShell::AfterProcessNextEvent(nsIThreadInternal *aThread,
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 
+// applicationDidBecomeActive
+//
+// Make sure gLastModifierState is updated when we become active (since we
+// won't have received [ChildView flagsChanged:] messages while inactive).
+- (void)applicationDidBecomeActive:(NSNotification*)aNotification
+{
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // [NSEvent modifierFlags] is valid on every kind of event, so we don't need
+  // to worry about getting an NSInternalInconsistencyException here.
+  NSEvent* currentEvent = [NSApp currentEvent];
+  if (currentEvent) {
+    gLastModifierState =
+      nsCocoaUtils::GetCocoaEventModifierFlags(currentEvent) & NSDeviceIndependentModifierFlagsMask;
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
 // beginMenuTracking
 //
 // Roll up our context menu (if any) when some other app (or the OS) opens

widget/src/cocoa/nsChildView.h

@@ -174,8 +174,6 @@ enum {
   // when handling |draggingUpdated:| messages.
   nsIDragService* mDragService;
   
-  PRUint32 mLastModifierState;
-
   // For use with plugins, so that we can support IME in them.  We can't use
   // Cocoa TSM documents (those created and managed by the NSTSMInputContext
   // class) -- for some reason TSMProcessRawKeyEvent() doesn't work with them.

widget/src/cocoa/nsChildView.mm

@@ -136,6 +136,8 @@ static void blinkRgn(RgnHandle rgn);
 nsIRollupListener * gRollupListener = nsnull;
 nsIWidget         * gRollupWidget   = nsnull;
 
+PRUint32 gLastModifierState = 0;
+
 
 @interface ChildView(Private)
 
@@ -6021,10 +6023,7 @@ static BOOL keyUpAlreadySentKeyDown = NO;
 
   // CapsLock state and other modifier states are different:
   // CapsLock state does not revert when the CapsLock key goes up, as the
-  // modifier state does for other modifier keys on key up. Also,
-  // mLastModifierState is set only when this view is the first responder. We
-  // cannot trust mLastModifierState to accurately reflect the state of CapsLock
-  // since CapsLock maybe have been toggled when another window was active.
+  // modifier state does for other modifier keys on key up.
   if ([theEvent keyCode] == kCapsLockKeyCode) {
     // Fire key down event for caps lock.
     [self fireKeyEventForFlagsChanged:theEvent keyDown:YES];
@@ -6043,7 +6042,7 @@ static BOOL keyUpAlreadySentKeyDown = NO;
 
     for (PRUint32 i = 0; i < kModifierCount; i++) {
       PRUint32 modifierBit = kModifierMaskTable[i];
-      if ((modifiers & modifierBit) != (mLastModifierState & modifierBit)) {
+      if ((modifiers & modifierBit) != (gLastModifierState & modifierBit)) {
         BOOL isKeyDown = (modifiers & modifierBit) != 0 ? YES : NO;
 
         [self fireKeyEventForFlagsChanged:theEvent keyDown:isKeyDown];
@@ -6058,7 +6057,7 @@ static BOOL keyUpAlreadySentKeyDown = NO;
       }
     }
 
-    mLastModifierState = modifiers;
+    gLastModifierState = modifiers;
   }
 
   // check if the hand scroll cursor needs to be set/unset