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 187 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.
-    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;
-
     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);
     return CreateSucceeded;
@@ skipping 889 matching lines @@
   // SwapBuffers.
   proxy_->ForceSerializeOnSwapBuffers();
 }
 
 bool LayerTreeHost::AlwaysUsePartialTextureUpdates() {
   if (!proxy_->GetRendererCapabilities().allow_partial_texture_updates)
     return false;
   return !proxy_->HasImplThread();
 }
 
+size_t LayerTreeHost::MaxPartialTextureUpdates() const {
+  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());
+  }
+  return max_partial_texture_updates;
+}
+
 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