Extend the suppression for bug 26920.

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 # running overnight and removing outdated bugs/suppressions.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 137 matching lines @@
    fun:IPCChannelTest_ChannelProxyTest_Test::TestBody
 }
 # TODO(glider): deal with asterisks in stack traces
 # (like "CancelableTask* NewRunnableMethod" here)
 {
    bug_26920_b
    Heapcheck:Leak
    ...
    fun:IPC::ChannelProxy::Context::OnChannelError
    fun:IPC::Channel::ChannelImpl::OnFileCanReadWithoutBlocking
-   fun:base::MessagePumpLibevent::FileDescriptorWatcher::OnFileCanReadWithoutBlocking
+   ...
    fun:base::MessagePumpLibevent::OnLibeventNotification
    fun:event_process_active
    fun:event_base_loop
 }
 {
    bug_26920_c
    Heapcheck:Leak
    fun:__gnu_cxx::new_allocator::allocate
    fun:std::string::_Rep::_S_create
    ...
@@ skipping 242 matching lines @@
    Heapcheck:Leak
    fun:Callback1::Type* NewCallback
    fun:media::VideoDecoderImpl::DoInitialize
 }
 {
    bug_45072
    Heapcheck:Leak
    fun:::RunTest_EnsureTaskDeletion*
    fun:MessageLoopTest_*EnsureTaskDeletion_*::TestBody
 }