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

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 611d6aee0a1df4c242c2ece7b9c88a8bc557ea5c..a7e500520db337de6fcbc64d8783158c26fd7ca9 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -182,16 +182,6 @@ LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted(bool success) {
   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_ =
@@ -1085,7 +1075,14 @@ void LayerTreeHost::RateLimit() {
 }
 
 bool LayerTreeHost::RequestPartialTextureUpdate() {
-  if (partial_texture_update_requests_ >= settings_.max_partial_texture_updates)
+  size_t max_partial_texture_updates = settings_.max_partial_texture_updates;

[danakj, 2013/09/17 22:44:23]

Oh, this should be 0 if the if statement below is false. Set it to 0 here, and
use the settings_ value inside the std::min statement on 1081. (Sorry for
missing that change in logic)

+  if (proxy_->GetRendererCapabilities().allow_partial_texture_updates &&
+      !settings_.impl_side_painting) {
+    max_partial_texture_updates = std::min(max_partial_texture_updates,
+                                           proxy_->MaxPartialTextureUpdates());
+  }
+
+  if (partial_texture_update_requests_ >= max_partial_texture_updates)
     return false;
 
   partial_texture_update_requests_++;