Suppress all the leaks from ExtensionPrefStoreTest

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 # running overnight and removing outdated bugs/suppressions.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 821 matching lines @@
    fun:MessageLoop::DoWork
    fun:base::MessagePumpDefault::Run
    fun:MessageLoop::RunInternal
    fun:MessageLoop::RunHandler
    fun:MessageLoop::Run
    fun:base::Thread::Run
    fun:base::Thread::ThreadMain
    fun:ThreadFunc
    fun:start_thread
 }
+{
+   48980_a
+   Heapcheck:Leak
+   fun:MockPrefService
+   fun:ExtensionPrefStoreTest_NotifyWhenNeeded_Test::TestBody
+}
+{
+   48980_b
+   Heapcheck:Leak
+   ...
+   fun:PrefService::RegisterStringPref
+   fun:ExtensionPrefStoreTest_*_Test::TestBody
+}
+{
+   48980_c
+   Heapcheck:Leak
+   ...
+   fun:ExtensionPrefStore::InstallExtensionPref
+}
+{
+   48980_d
+   Heapcheck:Leak
+   ...
+   fun:basic_string
+   fun:ExtensionPrefStoreTest_*_Test::TestBody
+}
+{
+   48980_e
+   Heapcheck:Leak
+   fun:Value::CreateStringValue
+   fun:ExtensionPrefStoreTest_*_Test::TestBody
+}