mac: Fix sending of mouse moved events after resizing window's lower left corner

ui/base/cocoa/base_view.mm

Index: ui/base/cocoa/base_view.mm
diff --git a/ui/base/cocoa/base_view.mm b/ui/base/cocoa/base_view.mm
index d5f89e89aadf8570a0872d8c3ae80d11a3d447a7..ad1f1fec6f90c3ad8e7f2f987c60891247e5bb93 100644
--- a/ui/base/cocoa/base_view.mm
+++ b/ui/base/cocoa/base_view.mm
@@ -8,26 +8,15 @@ NSString* kViewDidBecomeFirstResponder =
     @"Chromium.kViewDidBecomeFirstResponder";
 NSString* kSelectionDirection = @"Chromium.kSelectionDirection";
 
-@implementation BaseView
+const int kTrackingOptions = NSTrackingMouseMoved |
+                             NSTrackingMouseEnteredAndExited |
+                             NSTrackingActiveAlways;
 
-- (id)initWithFrame:(NSRect)frame {
-  self = [super initWithFrame:frame];
-  if (self) {
-    trackingArea_ =
-        [[NSTrackingArea alloc] initWithRect:frame
-                                     options:NSTrackingMouseMoved |
-                                             NSTrackingMouseEnteredAndExited |
-                                             NSTrackingActiveInActiveApp |
-                                             NSTrackingInVisibleRect
-                                       owner:self
-                                    userInfo:nil];
-    [self addTrackingArea:trackingArea_];
-  }
-  return self;
-}
+@implementation BaseView
 
 - (void)dealloc {
-  [self removeTrackingArea:trackingArea_];
+  if (trackingArea_)
+    [self removeTrackingArea:trackingArea_];
   [trackingArea_ release];
 
   [super dealloc];
@@ -143,4 +132,20 @@ NSString* kSelectionDirection = @"Chromium.kSelectionDirection";
   return new_rect;
 }
 
+- (void)updateTrackingAreas {
+  [super updateTrackingAreas];
+
+  // NSTrackingInVisibleRect doesn't work correctly with Lion's window resizing,
+  // http://crbug.com/176725 /  http://openradar.appspot.com/radar?id=2773401 .
+  // Tear down old tracking area and create a new one as workaround.
+  if (trackingArea_)
+    [self removeTrackingArea:trackingArea_];
+  [trackingArea_ release];
+  trackingArea_ = [[NSTrackingArea alloc] initWithRect:[self frame]
+                                               options:kTrackingOptions
+                                                 owner:self
+                                              userInfo:nil];
+  [self addTrackingArea:trackingArea_];
+}
+
 @end