Fix Manifest leak in Extension::InitFromValue.

tools/heapcheck/suppressions.txt

 # There are three kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 1767 matching lines @@
    fun:::DefaultFocusManagerFactory::CreateFocusManager
    fun:views::FocusManagerFactory::Create
    fun:views::Widget::OnNativeWidgetCreated
    fun:views::NativeWidgetGtk::InitNativeWidget
    fun:views::Widget::Init
    fun:views::Widget::CreateWindowWithParentAndBounds
    fun:views::Widget::CreateWindowWithBounds
    fun:AccessibilityEventRouterViewsTest::CreateWindowWithContents
    fun:AccessibilityEventRouterViewsTest_TestFocusNotification_Test::TestBody
 }
-{
-   bug_106331_a
-   Heapcheck:Leak
-   ...
-   fun:Extension::Create
-}
-{
-   bug_106331_b
-   Heapcheck:Leak
-   ...
-   fun:ExtensionUnpacker::ReadManifest
-   fun:ExtensionUnpacker::Run
-}
-{
-   bug_106331_c
-   Heapcheck:Leak
-   ...
-   fun:JSONFileValueSerializer::Deserialize
-   fun:::FileThreadDeserializer::DoReading
-   fun:JsonPrefStore::ReadPrefs
-   fun:PrefService::InitFromStorage
-   fun:PrefService*
-   fun:PrefServiceMockBuilder::Create
-   fun:ExtensionServiceTestBase::InitializeExtensionService
-   fun:ExtensionServiceTestBase::InitializeInstalledExtensionService
-   fun:ExtensionServiceTest_UninstallingNotLoadedExtension_Test::TestBody
-}