Two tweaks for accelerated painting:

. Make sure if there is no texture and we're told to paint, we paint
  to the whole texture (see comment for details on why we need to do
  this).
. When the transform changes only schedule paint on the widget. By doing
  this we won't trigger updating the texture, only having the
  compositor redraw everything. This currently doesn't matter, but
  will once James lands his changes to SchedulePaint to keep a dirty
  bit.

BUG=none
TEST=none
R=ben@chromium.org,wjmaclean@chromium.org

Review URL: http://codereview.chromium.org/7056013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86139 0039d316-1c4b-4281-b951-d872f2087c98

views/view.cc

@@ -413,8 +413,22 @@ void View::SetTransform(const ui::Transform& transform) {
     SchedulePaint();
   } else {
     transform_.reset(new ui::Transform(transform));
-    // TODO: this needs to trigger a paint on the widget. It shouldn't use
-    // SchedulePaint as we don't want to mark the views dirty.
+#if defined(COMPOSITOR_2)
+    if (!texture_.get()) {
+      // We don't yet have a texture. SchedulePaint so one is created.
+      SchedulePaint();
+    } else {
+      // We have a texture. When the transform changes and the texture is up to
+      // date we don't want to SchedulePaint as it'll trigger painting to the
+      // texture. Instead we tell the Widget to paint, which makes the
+      // compositor draw using the existing texture.
+      // We schedule paint the complete bounds as compositor generally don't
+      // support partial painting.
+      Widget* widget = GetWidget();
+      if (widget)
+        widget->SchedulePaintInRect(widget->GetRootView()->bounds());
+    }
+#endif
   }
 }
 
@@ -1169,9 +1183,19 @@ void View::PaintToTexture(const gfx::Rect& dirty_region) {
     return;
 
   if (ShouldPaintToTexture() && texture_needs_updating_) {
-    texture_clip_rect_ = dirty_region;
-    Paint(NULL);
-    texture_clip_rect_.SetRect(0, 0, 0, 0);
+    if (!texture_.get()) {
+      // If we have no texture paint the whole view. We do this to handle two
+      // cases:
+      // . Workaround for WidgetWin/WindowWin. In particular its possible to
+      //   create the rootview at the non-client size, even though we'll never
+      //   paint at that size.
+      // . In case the texture is recreated and a partial paint was scheduled.
+      Paint(NULL);
+    } else {
+      texture_clip_rect_ = dirty_region;
+      Paint(NULL);
+      texture_clip_rect_.SetRect(0, 0, 0, 0);
+    }
   } else {
     // Forward to all children as a descendant may be dirty and have a texture.
     for (int i = child_count() - 1; i >= 0; --i) {