Don't expect ack for ViewMsg_OnResize if backing size is empty

content/browser/renderer_host/render_widget_host_unittest.cc

Index: content/browser/renderer_host/render_widget_host_unittest.cc
diff --git a/content/browser/renderer_host/render_widget_host_unittest.cc b/content/browser/renderer_host/render_widget_host_unittest.cc
index 84945b9da1bbdd3f44898b52f147232a10660f77..6376b99cf44fc3f8e113df2f98db284fe197cf9e 100644
--- a/content/browser/renderer_host/render_widget_host_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_unittest.cc
@@ -516,11 +516,27 @@ class TestView : public TestRenderWidgetHostView {
     acked_event_ = touch;
     ++acked_event_count_;
   }
+  virtual gfx::Size GetPhysicalBackingSize() const OVERRIDE {
+    if (use_custom_physical_backing_size_)
+      return custom_physical_backing_size_;
+    return TestRenderWidgetHostView::GetPhysicalBackingSize();
+  }
+
+  void SetCustomPhysicalBackingSize(const gfx::Size& physical_backing_size) {
+    use_custom_physical_backing_size_ = true;
+    custom_physical_backing_size_ = physical_backing_size;
+  }
+
+  void ClearCustomPhysicalBackingSize() {
+    use_custom_physical_backing_size_ = false;
+  }
 
  protected:
   WebTouchEvent acked_event_;
   int acked_event_count_;
   gfx::Rect bounds_;
+  bool use_custom_physical_backing_size_;
+  gfx::Size custom_physical_backing_size_;
 
   DISALLOW_COPY_AND_ASSIGN(TestView);
 };
@@ -863,10 +879,20 @@ TEST_F(RenderWidgetHostTest, Resize) {
   EXPECT_EQ(gfx::Size(), host_->in_flight_size_);
   EXPECT_FALSE(process_->sink().GetUniqueMessageMatching(ViewMsg_Resize::ID));
 
-  // Setting the bounds to a "real" rect should send out the notification.
+  // Setting the bounds to a "real" rect should send out the notification,
+  // but should not expect ack for empty physical backing size.
   gfx::Rect original_size(0, 0, 100, 100);
   process_->sink().ClearMessages();
   view_->set_bounds(original_size);
+  view_->SetCustomPhysicalBackingSize(gfx::Size());
+  host_->WasResized();
+  EXPECT_FALSE(host_->resize_ack_pending_);
+  EXPECT_EQ(original_size.size(), host_->in_flight_size_);
+  EXPECT_TRUE(process_->sink().GetUniqueMessageMatching(ViewMsg_Resize::ID));
+
+  // Setting the bounds to a "real" rect should send out the notification.
+  process_->sink().ClearMessages();
+  view_->ClearCustomPhysicalBackingSize();
   host_->WasResized();
   EXPECT_TRUE(host_->resize_ack_pending_);
   EXPECT_EQ(original_size.size(), host_->in_flight_size_);