Apply a CursorRect to the extent of the render widget view for web page cursors.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 1d3ae76c5c430b830f661fe723811890dd0b3624..87d31b3817d6ae7570de7e542042f790135a79d3 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -546,32 +546,14 @@ gfx::Rect RenderWidgetHostViewMac::GetViewBounds() const {
 }
 
 void RenderWidgetHostViewMac::UpdateCursor(const WebCursor& cursor) {
-  current_cursor_ = cursor;
-  UpdateCursorIfNecessary();
-}
-
-void RenderWidgetHostViewMac::UpdateCursorIfNecessary() {
-  // Do something special (as Win Chromium does) for arrow cursor while loading
-  // a page? TODO(avi): decide
-
-  // Don't update the cursor if a context menu is being shown.
-  if (IsShowingContextMenu())
-    return;
-
-  // Can we synchronize to the event stream? Switch to -[NSWindow
-  // mouseLocationOutsideOfEventStream] if we cannot. TODO(avi): test and see
-  NSEvent* event = [[cocoa_view_ window] currentEvent];
-  if ([event window] != [cocoa_view_ window])
-    return;
-
-  NSCursor* ns_cursor = current_cursor_.GetNativeCursor();
-  [ns_cursor set];
+  WebCursor web_cursor = cursor;

[Avi (use Gerrit), 2012/05/24 15:14:49]

Why this copy? If GetNativeCursor() isn't const, can you make it?

+  [cocoa_view_ updateCursor:web_cursor.GetNativeCursor()];
 }
 
 void RenderWidgetHostViewMac::SetIsLoading(bool is_loading) {
   is_loading_ = is_loading;
   // If we ever decide to show the waiting cursor while the page is loading
-  // like Chrome does on Windows, call |UpdateCursorIfNecessary()| here.
+  // like Chrome does on Windows, call |UpdateCursor()| here.
 }
 
 void RenderWidgetHostViewMac::TextInputStateChanged(
@@ -751,11 +733,6 @@ void RenderWidgetHostViewMac::SelectionChanged(const string16& text,
 void RenderWidgetHostViewMac::SetShowingContextMenu(bool showing) {
   content::RenderWidgetHostViewBase::SetShowingContextMenu(showing);
 
-  // If the menu was closed, restore the cursor to the saved version initially,
-  // as the renderer will not re-send it if there was no change.
-  if (!showing)
-    UpdateCursorIfNecessary();
-
   // Create a fake mouse event to inform the render widget that the mouse
   // left or entered.
   NSWindow* window = [cocoa_view_ window];
@@ -1244,6 +1221,8 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
 - (id)initWithRenderWidgetHostViewMac:(RenderWidgetHostViewMac*)r {
   self = [super initWithFrame:NSZeroRect];
   if (self) {
+    current_cursor_ = nil;
+
     editCommand_helper_.reset(new RenderWidgetHostViewMacEditCommandHelper);
     editCommand_helper_->AddEditingSelectorsToClass([self class]);
 
@@ -1267,9 +1246,17 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
     [delegate_ viewGone:self];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 
+  [current_cursor_ release];
+  current_cursor_ = nil;
+
   [super dealloc];
 }
 
+- (void)resetCursorRects {
+  [self addCursorRect:[self visibleRect] cursor:current_cursor_];
+  [current_cursor_ setOnMouseEntered:YES];
+}
+
 - (void)setRWHVDelegate:(NSObject<RenderWidgetHostViewMacDelegate>*)delegate {
   delegate_ = delegate;
 }
@@ -2869,6 +2856,15 @@ extern NSString *NSTextInputReplacementRangeAttributeName;
     widget->Send(new ViewMsg_SetInLiveResize(widget->GetRoutingID(), false));
 }
 
+- (void)updateCursor:(NSCursor*)cursor {
+  if (current_cursor_ == cursor)
+    return;
+
+  [current_cursor_ release];
+  current_cursor_ = [cursor retain];
+  [[self window] invalidateCursorRectsForView:self];

[Avi (use Gerrit), 2012/05/24 15:14:49]

That is... elegant. Wow.

+}
+
 @end
 
 //