Implement on demand quad rasterization for PicturePiles.

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 d9872514d5b12cc5ebf739fbba8ac59c955b69a2..70104e64b2f9fc0b064fa41b9388ec8a2ad71fd8 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -269,6 +269,41 @@ ResourceProvider::ResourceId ResourceProvider::CreateResourceFromTextureMailbox(
   return id;
 }
 
+void ResourceProvider::ResizeResource(ResourceId id, gfx::Size size) {

[reveman, 2013/03/22 23:56:50]

I don't understand why we need this function.

[Leandro Graciá Gil, 2013/03/25 15:21:02]

Considering all the details that need to be tracked and the problems this might
introduce, I'm reviewing the assumptions that led to introducing this function.
I'll make an overall comment in the next iteration of the patch.

+  DCHECK(thread_checker_.CalledOnValidThread());
+  ResourceMap::iterator it = resources_.find(id);
+  CHECK(it != resources_.end());
+  Resource* resource = &it->second;
+  DCHECK(!resource->lock_for_read_count);
+  DCHECK(!resource->marked_for_deletion);
+  DCHECK(resource->pending_set_pixels || !resource->locked_for_write);
+  DCHECK(!resource->exported);
+  DCHECK(!resource->external);
+  DCHECK(!resource->gl_pixel_buffer_id && !resource->pixel_buffer);
+
+  if (resource->size != size) {
+    switch (resource->type) {
+    case GLTexture:
+      DCHECK_LE(size.width(), max_texture_size_);
+      DCHECK_LE(size.height(), max_texture_size_);
+      resource->allocated = false;
+      break;
+

[piman, 2013/03/22 20:52:34]

nit: no need for blank line.

+    case Bitmap:
+      DCHECK(resource->pixels);
+      delete[] resource->pixels;
+      resource->pixels = new uint8_t[size.width() * size.height() * 4];
+      resource->allocated = true;
+      break;
+
+    default:
+      NOTREACHED();

[piman, 2013/03/22 20:52:34]

nit: we usually don't add the default clause when switching on an enum, so that
we get a compiler warning if adding an enum value.

+    }
+
+    resource->size = size;
+  }
+}
+
 void ResourceProvider::DeleteResource(ResourceId id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   ResourceMap::iterator it = resources_.find(id);