Bug 926497 - Prevent the favicon cache from throwing NPEs at odd moments. r=rnewman

mobile/android/base/favicons/Favicons.java

@@ -351,6 +351,7 @@ public class Favicons {
                            "/favicon.ico", null,
                            null).toString();
         } catch (URISyntaxException e) {
+            Log.e(LOGTAG, "URISyntaxException getting default favicon URL", e);
             return null;
         }
     }

mobile/android/base/favicons/LoadFaviconTask.java

@@ -234,6 +234,10 @@ public class LoadFaviconTask extends UiAsyncTask<Void, Void, Bitmap> {
             } else {
                 // If we don't have a stored one, fall back to the default.
                 mFaviconUrl = Favicons.guessDefaultFaviconURL(mPageUrl);
+
+                if (TextUtils.isEmpty(mFaviconUrl)) {
+                    return null;
+                }
                 isUsingDefaultURL = true;
             }
         }

mobile/android/base/favicons/cache/FaviconCache.java

@@ -205,6 +205,10 @@ public class FaviconCache {
      * @return true if this favicon is blacklisted, false otherwise.
      */
     public boolean isFailedFavicon(String faviconURL) {
+        if (faviconURL == null) {
+            return true;
+        }
+
         startRead();
 
         boolean isExpired = false;
@@ -241,7 +245,7 @@ public class FaviconCache {
             // Flag to prevent finally from doubly-unlocking.
             isAborting = true;
             Log.e(LOGTAG, "FaviconCache exception!", unhandled);
-            return false;
+            return true;
         }  finally {
             if (!isAborting) {
                 if (isExpired) {