memory coordinator: Check RenderProcessHost pointers before use them

content/browser/memory/memory_coordinator.cc

 // Copyright 2016 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 "content/browser/memory/memory_coordinator.h"
 
 #include "base/memory/memory_coordinator_client_registry.h"
 #include "base/metrics/histogram_macros.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/render_process_host.h"
@@ skipping 151 matching lines @@
   children_.erase(render_process_id);
 }
 
 bool MemoryCoordinator::CanThrottleRenderer(int render_process_id) {
   // If there is no delegate (i.e. tests), renderers are always throttleable.
   // TODO(bashi): We check |delegate_| to avoid calling FromID() on a
   // wrong thread in tests. Figure out a better way to handle tests.
   if (!delegate_)
     return true;
   auto* render_process_host = RenderProcessHost::FromID(render_process_id);
-  return render_process_host->IsProcessBackgrounded();
+  return render_process_host && render_process_host->IsProcessBackgrounded();
 }
 
 bool MemoryCoordinator::CanSuspendRenderer(int render_process_id) {
   // If there is no delegate (i.e. tests), renderers are always suspendable.
   if (!delegate_)
     return true;
   auto* render_process_host = RenderProcessHost::FromID(render_process_id);
-  if (!render_process_host->IsProcessBackgrounded())
-      return false;
+  if (!render_process_host || !render_process_host->IsProcessBackgrounded())
+    return false;
   return delegate_->CanSuspendBackgroundedRenderer(render_process_id);
 }
 
 void MemoryCoordinator::CreateChildInfoMapEntry(
     int render_process_id,
     std::unique_ptr<MemoryCoordinatorHandleImpl> handle) {
   auto& child_info = children_[render_process_id];
   // Process always start with normal memory state.
   // TODO(chrisha): Consider having memory state be a startup parameter of
   // child processes, allowing them to be launched in a restricted state.
   child_info.memory_state = mojom::MemoryState::NORMAL;
   child_info.handle = std::move(handle);
 }
 
 MemoryCoordinator::ChildInfo::ChildInfo() {}
 
 MemoryCoordinator::ChildInfo::ChildInfo(const ChildInfo& rhs) {
   // This is a nop, but exists for compatibility with STL containers.
 }
 
 MemoryCoordinator::ChildInfo::~ChildInfo() {}
 
 }  // namespace content