Add PreferHtmlOverPlugins feature and don't advertise Flash when it's enabled.

BUG=626728

Review-Url: https://codereview.chromium.org/2154603003
Cr-Commit-Position: refs/heads/master@{#405911}

chrome/browser/plugins/chrome_plugin_service_filter.cc

@@ -17,6 +17,7 @@
 #include "chrome/browser/plugins/plugin_metadata.h"
 #include "chrome/browser/plugins/plugin_prefs.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/content_settings/content/common/content_settings_messages.h"
@@ -30,6 +31,7 @@
 #include "content/public/browser/resource_context.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/content_constants.h"
 #include "grit/components_strings.h"
 #include "grit/theme_resources.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -104,6 +106,12 @@ bool ChromePluginServiceFilter::IsPluginAvailable(
     }
   }
 
+  // Check whether PreferHtmlOverPlugins feature is enabled.
+  if (plugin->name == base::ASCIIToUTF16(content::kFlashPluginName) &&
+      base::FeatureList::IsEnabled(features::kPreferHtmlOverPlugins)) {
+    return false;
+  }
+
   // Check whether the plugin is disabled.
   ResourceContextMap::iterator prefs_it =
       resource_context_map_.find(context);
@@ -224,4 +232,3 @@ ChromePluginServiceFilter::ProcessDetails::ProcessDetails(
 
 ChromePluginServiceFilter::ProcessDetails::~ProcessDetails() {
 }
-

chrome/common/chrome_features.cc

@@ -63,6 +63,11 @@ const base::Feature kMaterialDesignHistoryFeature {
 const base::Feature kMaterialDesignSettingsFeature{
     "MaterialDesignSettings", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Prefer HTML content by hiding Flash from the list of plugins.
+// https://crbug.com/626728
+const base::Feature kPreferHtmlOverPlugins{"PreferHtmlOverPlugins",
+                                           base::FEATURE_DISABLED_BY_DEFAULT};
+
 #if defined(OS_CHROMEOS)
 // Runtime flag that indicates whether this leak detector should be enabled in
 // the current instance of Chrome.

chrome/common/chrome_features.h

@@ -43,6 +43,8 @@ extern const base::Feature kMaterialDesignHistoryFeature;
 
 extern const base::Feature kMaterialDesignSettingsFeature;
 
+extern const base::Feature kPreferHtmlOverPlugins;
+
 #if defined(OS_CHROMEOS)
 extern const base::Feature kRuntimeMemoryLeakDetector;
 #endif  // defined(OS_CHROMEOS)