cc: Ensure that large damage doesn't register as "frame has no damage"

cc/debug/debug_rect_history.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/debug/debug_rect_history.h"
 
 #include <stddef.h>
 
 #include "base/memory/ptr_util.h"
 #include "cc/base/math_util.h"
@@ skipping 107 matching lines @@
 }
 
 void DebugRectHistory::SaveSurfaceDamageRects(
     const LayerImplList& render_surface_layer_list) {
   for (size_t i = 0; i < render_surface_layer_list.size(); ++i) {
     size_t surface_index = render_surface_layer_list.size() - 1 - i;
     LayerImpl* render_surface_layer = render_surface_layer_list[surface_index];
     RenderSurfaceImpl* render_surface = render_surface_layer->render_surface();
     DCHECK(render_surface);
 
-    debug_rects_.push_back(DebugRect(
-        SURFACE_DAMAGE_RECT_TYPE,
-        MathUtil::MapEnclosingClippedRect(
-            render_surface->screen_space_transform(),
-            render_surface->damage_tracker()->current_damage_rect())));
+    gfx::Rect damage_rect;
+    bool is_valid_rect =
+        render_surface->damage_tracker()->GetDamageRectIfValid(&damage_rect);

[enne (OOO), 2017/01/19 23:23:39]

Maybe encapsulate this conditional block in a RenderSurfaceImpl::GetDamageRect()
function since you do it three times?

[danakj, 2017/01/20 17:03:04]

My one thot on this is that then you have 2 ways to get a damage rect, one on
RSI and one on it's DamageTracker. It might be nice to not allow access to the
DamageTracker directly, but there's like 3 or 4 other methods we use from
LayerTreeHostImpl so idk..

[vmpstr, 2017/01/20 21:38:18]

I think it still makes sense, since the two accessors have slightly different
results: The RS one always returns a rect (if the damage was invalid, it just
returns the content rect). However, the damage tracker one provides more fine
grained information: either a rect, or information that the rect wasn't valid.

I agree that hiding damage tracker might be nice, but then that means adding
some forwarding functions to the render surface, which I'd like to avoid in this
patch.

[vmpstr, 2017/01/20 21:38:18]

Done.

+    if (!is_valid_rect)
+      damage_rect = render_surface->content_rect();
+    debug_rects_.push_back(
+        DebugRect(SURFACE_DAMAGE_RECT_TYPE,
+                  MathUtil::MapEnclosingClippedRect(
+                      render_surface->screen_space_transform(), damage_rect)));
   }
 }
 
 void DebugRectHistory::SaveScreenSpaceRects(
     const LayerImplList& render_surface_layer_list) {
   for (size_t i = 0; i < render_surface_layer_list.size(); ++i) {
     size_t surface_index = render_surface_layer_list.size() - 1 - i;
     LayerImpl* render_surface_layer = render_surface_layer_list[surface_index];
     RenderSurfaceImpl* render_surface = render_surface_layer->render_surface();
     DCHECK(render_surface);
@@ skipping 92 matching lines @@
     debug_rects_.push_back(
         DebugRect(ANIMATION_BOUNDS_RECT_TYPE,
                   gfx::ToEnclosingRect(gfx::RectF(inflated_bounds.x(),
                                                   inflated_bounds.y(),
                                                   inflated_bounds.width(),
                                                   inflated_bounds.height()))));
   }
 }
 
 }  // namespace cc