cc: Prevent the tile manager from allocating more memory than allowed.

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 5835db565d31ec048c44d252a38421722cb1b1c8..208ab11357333de89363e0e1954760bb7f175343 100644
--- a/cc/resources/resource_pool.cc
+++ b/cc/resources/resource_pool.cc
@@ -31,9 +31,10 @@ ResourcePool::ResourcePool(ResourceProvider* resource_provider)
     : resource_provider_(resource_provider),
       max_memory_usage_bytes_(0),
       max_unused_memory_usage_bytes_(0),
+      max_resource_count_(0),
       memory_usage_bytes_(0),
       unused_memory_usage_bytes_(0),
-      num_resources_limit_(0) {
+      resource_count_(0) {
 }
 
 ResourcePool::~ResourcePool() {
@@ -63,8 +64,7 @@ scoped_ptr<ResourcePool::Resource> ResourcePool::AcquireResource(
   }
 
   // Create new resource.
-  Resource* resource = new Resource(
-      resource_provider_, size, format);
+  Resource* resource = new Resource(resource_provider_, size, format);
 
   // Extend all read locks on all resources until the resource is
   // finished being used, such that we know when resources are
@@ -72,6 +72,7 @@ scoped_ptr<ResourcePool::Resource> ResourcePool::AcquireResource(
   resource_provider_->EnableReadLockFences(resource->id(), true);
 
   memory_usage_bytes_ += resource->bytes();
+  ++resource_count_;
   return make_scoped_ptr(resource);
 }
 
@@ -79,6 +80,7 @@ void ResourcePool::ReleaseResource(
     scoped_ptr<ResourcePool::Resource> resource) {
   if (MemoryUsageTooHigh()) {
     memory_usage_bytes_ -= resource->bytes();
+    --resource_count_;
     return;
   }
 
@@ -89,11 +91,15 @@ void ResourcePool::ReleaseResource(
 void ResourcePool::SetMemoryUsageLimits(
     size_t max_memory_usage_bytes,
     size_t max_unused_memory_usage_bytes,
-    size_t num_resources_limit) {
+    size_t max_resource_count) {
   max_memory_usage_bytes_ = max_memory_usage_bytes;
   max_unused_memory_usage_bytes_ = max_unused_memory_usage_bytes;
-  num_resources_limit_ = num_resources_limit;
+  max_resource_count_ = max_resource_count;
 
+  ReduceMemoryUsage();
+}
+
+void ResourcePool::ReduceMemoryUsage() {
   while (!resources_.empty()) {
     if (!MemoryUsageTooHigh())
       break;
@@ -104,12 +110,13 @@ void ResourcePool::SetMemoryUsageLimits(
     resources_.pop_back();
     memory_usage_bytes_ -= resource->bytes();
     unused_memory_usage_bytes_ -= resource->bytes();
+    --resource_count_;
     delete resource;
   }
 }
 
 bool ResourcePool::MemoryUsageTooHigh() {
-  if (resources_.size() > num_resources_limit_)
+  if (resource_count_ > max_resource_count_)
     return true;
   if (memory_usage_bytes_ > max_memory_usage_bytes_)
     return true;