Clean up error handling logic for extension tab muting

chrome/browser/ui/tabs/tab_utils.h

Index: chrome/browser/ui/tabs/tab_utils.h
diff --git a/chrome/browser/ui/tabs/tab_utils.h b/chrome/browser/ui/tabs/tab_utils.h
index 2ca81514a81b2d0486e6534def812969cb610cd2..358e2594671ca0acf6943fb73073149162f7ddd2 100644
--- a/chrome/browser/ui/tabs/tab_utils.h
+++ b/chrome/browser/ui/tabs/tab_utils.h
@@ -7,7 +7,7 @@
 
 #include <string>
 #include <vector>
-
+#include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ -33,6 +33,13 @@ enum TabMediaState {
   TAB_MEDIA_STATE_AUDIO_MUTING,  // Tab audio is being muted.
 };
 
+enum TabMutedResult {
+  TAB_MUTED_RESULT_SUCCESS,
+  TAB_MUTED_RESULT_FAIL_NOT_ENABLED,
+  TAB_MUTED_RESULT_FAIL_TABCAPTURE,
+  TAB_MUTED_RESULT_FAIL_RATE_LIMITED,
+};
+
 namespace chrome {
 
 // String to indicate reason for muted state change (user, capture, extension
@@ -40,6 +47,10 @@ namespace chrome {
 extern const char kMutedToggleCauseUser[];
 extern const char kMutedToggleCauseCapture[];
 
+// Constants for rate limiting mute updating by extensions
+extern const int kMuteTokenBucketCostSeconds;

[miu, 2015/07/18 00:42:42]

Just noticed this: Since these two constants are used only inside tab_utils.cc,
you don't need to declare them in the header file.  So, please delete these two
from this header file.

[Jared Sohn, 2015/07/18 23:57:24]

When this is done, I get an error message that says that the
kMuteTokenBucketCapacitySeconds variable used in the constructor for
LastMuteMetadata is undefined.  It will compile correctly if I define the
constants in the file prior to the struct, but now these variables are in the
global namespace but not externed.  Is this okay?

On 2015/07/18 at 00:42:42, miu wrote:

+extern const int kMuteTokenBucketCapacitySeconds;
+
 // Logic to determine which components (i.e., close button, favicon, and media
 // indicator) of a tab should be shown, given current state.  |capacity|
 // specifies how many components can be shown, given available tab width.
@@ -109,9 +120,9 @@ bool IsTabAudioMuted(content::WebContents* contents);
 
 // Sets whether all audio output from |contents| is muted.
 // Cause is extensionid, kMutedToggleCause constant, or empty string
-void SetTabAudioMuted(content::WebContents* contents,
-                      bool mute,
-                      const std::string& cause);
+TabMutedResult SetTabAudioMuted(content::WebContents* contents,
+                                bool mute,
+                                const std::string& cause);
 
 // Get cause of mute (extensionid, kMutedToggleCause constant, or empty string)
 const std::string& GetTabAudioMutedCause(content::WebContents* contents);