Remove ContextProvider::IsContextLost.

cc/raster/tile_task_worker_pool_perftest.cc

 // Copyright 2013 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 "cc/raster/tile_task_worker_pool.h"
 
 #include "base/test/test_simple_task_runner.h"
 #include "base/time/time.h"
 #include "cc/debug/lap_timer.h"
 #include "cc/output/context_provider.h"
@@ skipping 79 matching lines @@
         kOpenGL_GrBackend,
         reinterpret_cast<GrBackendContext>(null_interface.get())));
     return gr_context_.get();
   }
   void InvalidateGrContext(uint32_t state) override {
     if (gr_context_)
       gr_context_.get()->resetContext(state);
   }
   void SetupLock() override {}
   base::Lock* GetLock() override { return &context_lock_; }
-  bool IsContextLost() override { return false; }
   void VerifyContexts() override {}
   void DeleteCachedResources() override {}
   bool DestroyedOnMainThread() override { return false; }
   void SetLostContextCallback(const LostContextCallback& cb) override {}
   void SetMemoryPolicyChangedCallback(
       const MemoryPolicyChangedCallback& cb) override {}
 
  private:
   ~PerfContextProvider() override {}
 
@@ skipping 401 matching lines @@
   RunBuildTileTaskQueueTest("1_0", 1, 0);
   RunBuildTileTaskQueueTest("32_0", 32, 0);
   RunBuildTileTaskQueueTest("1_1", 1, 1);
   RunBuildTileTaskQueueTest("32_1", 32, 1);
   RunBuildTileTaskQueueTest("1_4", 1, 4);
   RunBuildTileTaskQueueTest("32_4", 32, 4);
 }
 
 }  // namespace
 }  // namespace cc