Shared Raster Worker Threads

cc/resources/raster_worker_pool.cc

Index: cc/resources/raster_worker_pool.cc
diff --git a/cc/resources/raster_worker_pool.cc b/cc/resources/raster_worker_pool.cc
index 06fd18e62e0ec2bdc9d440ee0ae6eb925c867ef4..ee11665012282557bc5f1618b2ca203f839d45c2 100644
--- a/cc/resources/raster_worker_pool.cc
+++ b/cc/resources/raster_worker_pool.cc
@@ -319,7 +319,9 @@ class RasterFinishedWorkerPoolTaskImpl : public internal::WorkerPoolTask {
   DISALLOW_COPY_AND_ASSIGN(RasterFinishedWorkerPoolTaskImpl);
 };
 
-const char* kWorkerThreadNamePrefix = "CompositorRaster";
+const int kDefaultNumRasterThreads = 1;
+
+int g_num_raster_threads = 0;
 
 }  // namespace
 
@@ -461,10 +463,24 @@ RasterWorkerPool::Task RasterWorkerPool::CreateImageDecodeTask(
                                                 reply));
 }
 
-RasterWorkerPool::RasterWorkerPool(ResourceProvider* resource_provider,
-                                   size_t num_threads)
-    : WorkerPool(num_threads, kWorkerThreadNamePrefix),
-      client_(NULL),
+// static
+void RasterWorkerPool::SetNumRasterThreads(int num_threads) {
+  DCHECK_LT(0, num_threads);
+  DCHECK_EQ(0, g_num_raster_threads);
+
+  g_num_raster_threads = num_threads;
+}
+
+// static
+int WorkerPool::GetNumRasterThreads() {
+  if (!g_num_raster_threads)
+    g_num_raster_threads = kDefaultNumRasterThreads;
+
+  return g_num_raster_threads;
+}
+
+RasterWorkerPool::RasterWorkerPool(ResourceProvider* resource_provider)
+    : client_(NULL),
       resource_provider_(resource_provider),
       weak_ptr_factory_(this) {
 }