Tab audio mute control (views UI), behind a switch (off by default).

chrome/browser/ui/tabs/tab_utils.cc

Index: chrome/browser/ui/tabs/tab_utils.cc
diff --git a/chrome/browser/ui/tabs/tab_utils.cc b/chrome/browser/ui/tabs/tab_utils.cc
index 84956d19d9407363313a12bc4873cce71d3d2557..998bfa26984476291e6f64dfddd34f3c18140d8f 100644
--- a/chrome/browser/ui/tabs/tab_utils.cc
+++ b/chrome/browser/ui/tabs/tab_utils.cc
@@ -4,9 +4,11 @@
 
 #include "chrome/browser/ui/tabs/tab_utils.h"
 
+#include "base/command_line.h"
 #include "base/strings/string16.h"
 #include "chrome/browser/media/media_capture_devices_dispatcher.h"
 #include "chrome/browser/media/media_stream_capture_indicator.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/grit/generated_resources.h"
 #include "content/public/browser/web_contents.h"
 #include "grit/theme_resources.h"
@@ -134,6 +136,8 @@ TabMediaState GetTabMediaStateForContents(content::WebContents* contents) {
       return TAB_MEDIA_STATE_RECORDING;
   }
 
+  if (IsTabAudioMutingFeatureEnabled() && contents->IsAudioMuted())
+    return TAB_MEDIA_STATE_AUDIO_MUTING;
   if (IsPlayingAudio(contents))
     return TAB_MEDIA_STATE_AUDIO_PLAYING;
 
@@ -145,6 +149,8 @@ const gfx::Image& GetTabMediaIndicatorImage(TabMediaState media_state) {
   switch (media_state) {
     case TAB_MEDIA_STATE_AUDIO_PLAYING:
       return rb.GetNativeImageNamed(IDR_TAB_AUDIO_INDICATOR);
+    case TAB_MEDIA_STATE_AUDIO_MUTING:
+      return rb.GetNativeImageNamed(IDR_TAB_AUDIO_MUTING_INDICATOR);
     case TAB_MEDIA_STATE_RECORDING:
       return rb.GetNativeImageNamed(IDR_TAB_RECORDING_INDICATOR);
     case TAB_MEDIA_STATE_CAPTURING:
@@ -156,6 +162,18 @@ const gfx::Image& GetTabMediaIndicatorImage(TabMediaState media_state) {
   return rb.GetNativeImageNamed(IDR_SAD_FAVICON);
 }
 
+const gfx::Image& GetTabMediaIndicatorAffordanceImage(
+    TabMediaState media_state) {
+  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
+  switch (media_state) {
+    case TAB_MEDIA_STATE_AUDIO_PLAYING:
+    case TAB_MEDIA_STATE_AUDIO_MUTING:
+      return rb.GetNativeImageNamed(IDR_TAB_AUDIO_MUTING_AFFORDANCE);
+    default:

[sky, 2014/09/23 22:58:17]

Can you explicitly list the states so that you get a compile error when a new
one is added (like you have on 241)?

[miu, 2014/09/24 22:34:15]

Done.

+      return GetTabMediaIndicatorImage(media_state);
+  }
+}
+
 scoped_ptr<gfx::Animation> CreateTabMediaIndicatorFadeAnimation(
     TabMediaState media_state) {
   if (media_state == TAB_MEDIA_STATE_RECORDING ||
@@ -191,6 +209,10 @@ base::string16 AssembleTabTooltipText(const base::string16& title,
       result.append(
           l10n_util::GetStringUTF16(IDS_TOOLTIP_TAB_MEDIA_STATE_AUDIO_PLAYING));
       break;
+    case TAB_MEDIA_STATE_AUDIO_MUTING:
+      result.append(
+          l10n_util::GetStringUTF16(IDS_TOOLTIP_TAB_MEDIA_STATE_AUDIO_MUTING));
+      break;
     case TAB_MEDIA_STATE_RECORDING:
       result.append(
           l10n_util::GetStringUTF16(IDS_TOOLTIP_TAB_MEDIA_STATE_RECORDING));
@@ -206,4 +228,27 @@ base::string16 AssembleTabTooltipText(const base::string16& title,
   return result;
 }
 
+bool IsTabAudioMutingFeatureEnabled() {
+#if defined(USE_AURA)
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableTabAudioMuting);
+#else
+  return false;
+#endif
+}
+
+bool CanToggleAudioMute(content::WebContents* contents) {
+  switch (GetTabMediaStateForContents(contents)) {
+    case TAB_MEDIA_STATE_NONE:
+    case TAB_MEDIA_STATE_AUDIO_PLAYING:
+    case TAB_MEDIA_STATE_AUDIO_MUTING:
+      return IsTabAudioMutingFeatureEnabled();
+    case TAB_MEDIA_STATE_RECORDING:
+    case TAB_MEDIA_STATE_CAPTURING:
+      return false;
+  }
+  NOTREACHED();
+  return false;
+}
+
 }  // namespace chrome