Change ResourcePool reuse to have looser size constraints.

cc/resources/resource_pool.cc

Index: cc/resources/resource_pool.cc
diff --git a/cc/resources/resource_pool.cc b/cc/resources/resource_pool.cc
index 41358702b7cf56683ab88608a09bdd5c5beac64f..1f0891b1e63446a3f3f3b6af1614c9f6fbae25b0 100644
--- a/cc/resources/resource_pool.cc
+++ b/cc/resources/resource_pool.cc
@@ -94,32 +94,53 @@ ResourcePool::~ResourcePool() {
   DCHECK_EQ(0u, total_resource_count_);
 }
 
-Resource* ResourcePool::ReuseResource(const gfx::Size& size,
+Resource* ResourcePool::ReuseResource(const gfx::Size& min_size,
+                                      const gfx::Size& max_size,
                                       ResourceFormat format,
                                       const gfx::ColorSpace& color_space) {
   // Finding resources in |unused_resources_| from MRU to LRU direction, touches
   // LRU resources only if needed, which increases possibility of expiring more
   // LRU resources within kResourceExpirationDelayMs.
+  ResourceDeque::iterator best_match = unused_resources_.end();
+  int64_t best_distance = std::numeric_limits<std::int64_t>::max();
   for (ResourceDeque::iterator it = unused_resources_.begin();
        it != unused_resources_.end(); ++it) {
     ScopedResource* resource = it->get();
-    DCHECK(resource_provider_->CanLockForWrite(resource->id()));
-
     if (resource->format() != format)
       continue;
-    if (resource->size() != size)
-      continue;
     if (resource->color_space() != color_space)
       continue;
+    if (resource->size() == min_size) {
+      best_match = it;
+      break;
+    }
 
-    // Transfer resource to |in_use_resources_|.
-    in_use_resources_[resource->id()] = std::move(*it);
-    unused_resources_.erase(it);
-    in_use_memory_usage_bytes_ += ResourceUtil::UncheckedSizeInBytes<size_t>(
-        resource->size(), resource->format());
-    return resource;
+    int32_t width = resource->size().width();
+    int32_t height = resource->size().height();
+    if (width < min_size.width() || width > max_size.width())
+      continue;
+    if (height < min_size.height() || height > max_size.height())
+      continue;
+
+    int64_t distance = width * height;
+    if (distance < best_distance) {
+      best_distance = distance;
+      best_match = it;
+    }
   }
-  return nullptr;
+
+  if (best_match == unused_resources_.end())
+    return nullptr;
+
+  ScopedResource* resource = best_match->get();
+  DCHECK(resource_provider_->CanLockForWrite(resource->id()));
+
+  // Transfer resource to |in_use_resources_|.
+  in_use_resources_[resource->id()] = std::move(*best_match);
+  unused_resources_.erase(best_match);
+  in_use_memory_usage_bytes_ += ResourceUtil::UncheckedSizeInBytes<size_t>(
+      resource->size(), resource->format());
+  return resource;
 }
 
 Resource* ResourcePool::CreateResource(const gfx::Size& size,
@@ -158,7 +179,7 @@ Resource* ResourcePool::CreateResource(const gfx::Size& size,
 Resource* ResourcePool::AcquireResource(const gfx::Size& size,
                                         ResourceFormat format,
                                         const gfx::ColorSpace& color_space) {
-  Resource* reused_resource = ReuseResource(size, format, color_space);
+  Resource* reused_resource = ReuseResource(size, size, format, color_space);
   if (reused_resource)
     return reused_resource;