cc: Reduce command buffer flushes related to creating texture ids.

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index 874fe3f641907df4c4e2b198316ce662d639b2a2..36c6f9e62727549997d32875d1fd6e7182a754e9 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -216,12 +216,14 @@ scoped_ptr<ResourceProvider> ResourceProvider::Create(
     OutputSurface* output_surface,
     SharedBitmapManager* shared_bitmap_manager,
     int highp_threshold_min,
-    bool use_rgba_4444_texture_format) {
+    bool use_rgba_4444_texture_format,
+    size_t texture_id_allocation_chunk_size) {
   scoped_ptr<ResourceProvider> resource_provider(
       new ResourceProvider(output_surface,
                            shared_bitmap_manager,
                            highp_threshold_min,
-                           use_rgba_4444_texture_format));
+                           use_rgba_4444_texture_format,
+                           texture_id_allocation_chunk_size));
 
   bool success = false;
   if (resource_provider->Context3d()) {
@@ -647,7 +649,7 @@ const ResourceProvider::Resource* ResourceProvider::LockForRead(ResourceId id) {
             context3d->waitSyncPoint(resource->mailbox.sync_point()));
         resource->mailbox.ResetSyncPoint();
       }
-      resource->gl_id = context3d->createTexture();
+      resource->gl_id = NextTextureId();
       GLC(context3d, context3d->bindTexture(resource->target, resource->gl_id));
       GLC(context3d,
           context3d->consumeTextureCHROMIUM(resource->target,
@@ -791,7 +793,8 @@ ResourceProvider::ScopedWriteLockSoftware::~ScopedWriteLockSoftware() {
 ResourceProvider::ResourceProvider(OutputSurface* output_surface,
                                    SharedBitmapManager* shared_bitmap_manager,
                                    int highp_threshold_min,
-                                   bool use_rgba_4444_texture_format)
+                                   bool use_rgba_4444_texture_format,
+                                   size_t texture_id_allocation_chunk_size)
     : output_surface_(output_surface),
       shared_bitmap_manager_(shared_bitmap_manager),
       lost_output_surface_(false),
@@ -804,8 +807,10 @@ ResourceProvider::ResourceProvider(OutputSurface* output_surface,
       use_shallow_flush_(false),
       max_texture_size_(0),
       best_texture_format_(RGBA_8888),
-      use_rgba_4444_texture_format_(use_rgba_4444_texture_format) {
+      use_rgba_4444_texture_format_(use_rgba_4444_texture_format),
+      texture_id_allocation_chunk_size_(texture_id_allocation_chunk_size) {
   DCHECK(output_surface_->HasClient());
+  DCHECK(texture_id_allocation_chunk_size_);
 }
 
 void ResourceProvider::InitializeSoftware() {
@@ -863,6 +868,14 @@ void ResourceProvider::CleanUpGLIfNeeded() {
   DCHECK(context3d);
   context3d->makeContextCurrent();
   texture_uploader_.reset();
+  if (!unused_texture_ids_.empty()) {
+    size_t size = unused_texture_ids_.size();
+    scoped_ptr<WebKit::WebGLId[]> ids(new WebKit::WebGLId[size]);
+    for (size_t i = 0; i < size; ++i)
+      ids[i] = unused_texture_ids_[i];
+    GLC(context3d, context3d->deleteTextures(size, ids.get()));
+    unused_texture_ids_.clear();
+  }
   Finish();
 }
 
@@ -988,7 +1001,7 @@ void ResourceProvider::ReceiveFromChild(
       // (and is simpler) to wait.
       if (it->sync_point)
         GLC(context3d, context3d->waitSyncPoint(it->sync_point));
-      GLC(context3d, texture_id = context3d->createTexture());
+      texture_id = NextTextureId();
       GLC(context3d, context3d->bindTexture(it->target, texture_id));
       GLC(context3d,
           context3d->consumeTextureCHROMIUM(it->target, it->mailbox.name));
@@ -1546,11 +1559,12 @@ void ResourceProvider::LazyCreate(Resource* resource) {
   if (resource->texture_pool == 0)
     return;
 
+  resource->gl_id = NextTextureId();
+
   WebGraphicsContext3D* context3d = Context3d();
   DCHECK(context3d);
 
   // Create and set texture properties. Allocation is delayed until needed.
-  GLC(context3d, resource->gl_id = context3d->createTexture());
   GLC(context3d, context3d->bindTexture(resource->target, resource->gl_id));
   GLC(context3d,
       context3d->texParameteri(
@@ -1729,4 +1743,20 @@ WebKit::WebGraphicsContext3D* ResourceProvider::Context3d() const {
   return context_provider ? context_provider->Context3d() : NULL;
 }
 
+unsigned ResourceProvider::NextTextureId() {
+  if (unused_texture_ids_.empty()) {
+    size_t size = texture_id_allocation_chunk_size_;
+    scoped_ptr<WebKit::WebGLId[]> ids(new WebKit::WebGLId[size]);
+    WebGraphicsContext3D* context3d = Context3d();
+    DCHECK(context3d);
+    GLC(context3d, context3d->genTextures(size, ids.get()));
+    unused_texture_ids_.assign(ids.get(), ids.get() + size);
+  }
+
+  unsigned gl_id = unused_texture_ids_.front();
+  unused_texture_ids_.pop_front();
+
+  return gl_id;
+}
+
 }  // namespace cc