Simplify plugin list refresh logic.

blink::ResetPluginCache, called by content/, currently tries to refresh
the browser plugin cache as well, but content/ also blocks this from
happening. We can simplify by simply not making this call in that case.

Change-Id: Ib61db31ab03a481ea9b7c485df03af384e177637
Bug: 846722
Reviewed-on: https://chromium-review.googlesource.com/1072499
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561871}

content/renderer/render_thread_impl.cc

@@ -2318,13 +2318,7 @@ void RenderThreadImpl::OnSystemColorsChanged(
 
 void RenderThreadImpl::PurgePluginListCache(bool reload_pages) {
 #if BUILDFLAG(ENABLE_PLUGINS)
-  // The call below will cause a GetPlugins call with refresh=true, but at this
-  // point we already know that the browser has refreshed its list, so disable
-  // refresh temporarily to prevent each renderer process causing the list to be
-  // regenerated.
-  blink_platform_impl_->set_plugin_refresh_allowed(false);
   blink::ResetPluginCache(reload_pages);
-  blink_platform_impl_->set_plugin_refresh_allowed(true);
 
   for (auto& observer : observers_)
     observer.PluginListChanged();

content/renderer/renderer_blink_platform_impl.cc

@@ -267,7 +267,6 @@ RendererBlinkPlatformImpl::RendererBlinkPlatformImpl(
       compositor_thread_(nullptr),
       main_thread_(main_thread_scheduler->CreateMainThread()),
       sudden_termination_disables_(0),
-      plugin_refresh_allowed_(true),
       default_task_runner_(main_thread_scheduler->DefaultTaskRunner()),
       web_scrollbar_behavior_(new WebScrollbarBehaviorImpl),
       main_thread_scheduler_(main_thread_scheduler) {
@@ -780,8 +779,6 @@ void RendererBlinkPlatformImpl::GetPluginList(
     blink::WebPluginListBuilder* builder) {
 #if BUILDFLAG(ENABLE_PLUGINS)
   std::vector<WebPluginInfo> plugins;
-  if (!plugin_refresh_allowed_)
-    refresh = false;
   RenderThread::Get()->Send(
       new FrameHostMsg_GetPlugins(refresh, mainFrameOrigin, &plugins));
   for (const WebPluginInfo& plugin : plugins) {

content/renderer/renderer_blink_platform_impl.h

@@ -74,9 +74,6 @@ class CONTENT_EXPORT RendererBlinkPlatformImpl : public BlinkPlatformImpl {
   // Shutdown must be called just prior to shutting down blink.
   void Shutdown();
 
-  void set_plugin_refresh_allowed(bool plugin_refresh_allowed) {
-    plugin_refresh_allowed_ = plugin_refresh_allowed;
-  }
   // Platform methods:
   blink::WebSandboxSupport* GetSandboxSupport() override;
   blink::WebCookieJar* CookieJar() override;
@@ -299,9 +296,6 @@ class CONTENT_EXPORT RendererBlinkPlatformImpl : public BlinkPlatformImpl {
   // we tell the browser to enable fast termination.
   int sudden_termination_disables_;
 
-  // If true, then a GetPlugins call is allowed to rescan the disk.
-  bool plugin_refresh_allowed_;
-
   std::unique_ptr<blink::WebIDBFactory> web_idb_factory_;
 
   std::unique_ptr<blink::WebBlobRegistry> blob_registry_;

third_party/blink/renderer/core/page/page.cc

@@ -75,8 +75,9 @@ namespace blink {
 
 // Wrapper function defined in WebKit.h
 void ResetPluginCache(bool reload_pages) {
+  // At this point we already know that the browser has refreshed its list, so
+  // it is not necessary to force it to be regenerated.
   DCHECK(!reload_pages);
-  Page::RefreshPlugins();
   Page::ResetPluginData();
 }
 
@@ -318,10 +319,6 @@ void Page::InitialStyleChanged() {
   }
 }
 
-void Page::RefreshPlugins() {
-  PluginData::RefreshBrowserSidePluginCache();
-}
-
 PluginData* Page::GetPluginData(const SecurityOrigin* main_frame_origin) {
   if (!plugin_data_)
     plugin_data_ = PluginData::Create();

third_party/blink/renderer/core/page/page.h

@@ -139,9 +139,6 @@ class CORE_EXPORT Page final : public GarbageCollectedFinalized<Page>,
   // Returns the plugin data associated with |main_frame_origin|.
   PluginData* GetPluginData(const SecurityOrigin* main_frame_origin);
 
-  // Refreshes the browser-side plugin cache.
-  static void RefreshPlugins();
-
   // Resets the plugin data for all pages in the renderer process and notifies
   // PluginsChangedObservers.
   static void ResetPluginData();

third_party/blink/renderer/modules/plugins/dom_plugin_array.cc

@@ -98,7 +98,7 @@ void DOMPluginArray::refresh(bool reload) {
   if (!GetFrame())
     return;
 
-  Page::RefreshPlugins();
+  PluginData::RefreshBrowserSidePluginCache();
   if (PluginData* data = GetPluginData())
     data->ResetPluginData();