Iterative cleanup for GL programs in GPU process

gpu/command_buffer/service/program_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/program_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 2464 matching lines @@
 }
 
 void ProgramManager::Destroy(bool have_context) {
   have_context_ = have_context;
 
   ProgramDeletionScopedUmaTimeAndRate scoped_histogram(
       base::saturated_cast<int32_t>(programs_.size()));
   programs_.clear();
 }
 
+bool ProgramManager::PreDestroyWithTimeout(bool have_context,
+                                           const base::TimeTicks& timeout) {
+  have_context_ = have_context;
+  for (auto it = programs_.begin(); it != programs_.end();) {
+    if (it->second->InUse()) {
+      // Can't delete in-use programs.
+      ++it;
+      continue;
+    }
+    if (base::TimeTicks::Now() > timeout)
+      return false;
+
+    it = programs_.erase(it);
+  }
+  return true;
+}
+
 void ProgramManager::StartTracking(Program* /* program */) {
   ++program_count_;
 }
 
 void ProgramManager::StopTracking(Program* /* program */) {
   --program_count_;
 }
 
 Program* ProgramManager::CreateProgram(
     GLuint client_id, GLuint service_id) {
@@ skipping 83 matching lines @@
   DCHECK(program);
   program->ClearUniforms(&zero_);
 }
 
 int32_t ProgramManager::MakeFakeLocation(int32_t index, int32_t element) {
   return index + element * 0x10000;
 }
 
 }  // namespace gles2
 }  // namespace gpu