LayerTreeHost should not modify the LayerTreeSettings object. Instead it should use a temporary va…

cc/trees/layer_tree_host.cc

 // Copyright 2011 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/trees/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 
 #include "base/bind.h"
@@ skipping 112 matching lines @@
       overdraw_bottom_height_(0.f),
       device_scale_factor_(1.f),
       visible_(true),
       page_scale_factor_(1.f),
       min_page_scale_factor_(1.f),
       max_page_scale_factor_(1.f),
       trigger_idle_updates_(true),
       background_color_(SK_ColorWHITE),
       has_transparent_background_(false),
       partial_texture_update_requests_(0),
+      max_partial_texture_updates_(settings_.max_partial_texture_updates),

[danakj, 2013/10/03 17:42:26]

Can we initialize this to 0?

       in_paint_layer_contents_(false),
       total_frames_used_for_lcd_text_metrics_(0),
       tree_id_(s_next_tree_id++) {
   if (settings_.accelerated_animation_enabled)
     animation_registrar_ = AnimationRegistrar::Create();
   s_num_layer_tree_instances++;
   rendering_stats_instrumentation_->set_record_rendering_stats(
       debug_state_.RecordRenderingStats());
 }
 
@@ skipping 55 matching lines @@
 LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted(bool success) {
   TRACE_EVENT1("cc",
                "LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted",
                "success",
                success);
 
   DCHECK(output_surface_lost_);
   if (success) {
     output_surface_lost_ = false;
 
-    // Update settings_ based on partial update capability.
+    // Update max_partial_texture_updates_ based on partial update capability.
     size_t max_partial_texture_updates = 0;
     if (proxy_->GetRendererCapabilities().allow_partial_texture_updates &&
         !settings_.impl_side_painting) {
       max_partial_texture_updates = std::min(
           settings_.max_partial_texture_updates,
           proxy_->MaxPartialTextureUpdates());
     }
-    settings_.max_partial_texture_updates = max_partial_texture_updates;
+    max_partial_texture_updates_ = max_partial_texture_updates;
 
     if (!contents_texture_manager_ &&
         (!settings_.impl_side_painting || !settings_.solid_color_scrollbars)) {
       contents_texture_manager_ =
           PrioritizedResourceManager::Create(proxy_.get());
       surface_memory_placeholder_ =
           contents_texture_manager_->CreateTexture(gfx::Size(), RGBA_8888);
     }
 
     client_->DidInitializeOutputSurface(true);
@@ skipping 885 matching lines @@
 }
 
 void LayerTreeHost::RateLimit() {
   // Force a no-op command on the compositor context, so that any ratelimiting
   // commands will wait for the compositing context, and therefore for the
   // SwapBuffers.
   proxy_->ForceSerializeOnSwapBuffers();
 }
 
 bool LayerTreeHost::RequestPartialTextureUpdate() {
-  if (partial_texture_update_requests_ >= settings_.max_partial_texture_updates)
+  if (partial_texture_update_requests_ >= MaxPartialTextureUpdates())
     return false;
 
   partial_texture_update_requests_++;
   return true;
 }
 
 void LayerTreeHost::SetDeviceScaleFactor(float device_scale_factor) {
   if (device_scale_factor == device_scale_factor_)
     return;
   device_scale_factor_ = device_scale_factor;
@@ skipping 103 matching lines @@
 void LayerTreeHost::RegisterViewportLayers(
     scoped_refptr<Layer> page_scale_layer,
     scoped_refptr<Layer> inner_viewport_scroll_layer,
     scoped_refptr<Layer> outer_viewport_scroll_layer) {
   page_scale_layer_ = page_scale_layer;
   inner_viewport_scroll_layer_ = inner_viewport_scroll_layer;
   outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
 }
 
 }  // namespace cc