[MemSheriff] Suppress uninit reads for Speech Recognition

NOTRY=true
TBR=benwells@chromium.org, burnik@chromium.org
BUG=422472

Review URL: https://codereview.chromium.org/647153002

Cr-Commit-Position: refs/heads/master@{#299175}

tools/valgrind/drmemory/suppressions.txt

@@ -692,3 +692,12 @@ shared_memory_support.dll!media::FromInterleavedInternal<>
 ...
 *!content::SpeechRecognitionAudioSinkTest::CaptureAudio
 *!content::SpeechRecognitionAudioSinkTest_SyncSocketFailsSendingData_Test::TestBody
+
+UNINITIALIZED READ
+name=http://crbug.com/422472 (d)
+content.dll!content::`anonymous namespace'::MaxAmplitude
+content.dll!content::MediaStreamAudioLevelCalculator::Calculate
+content.dll!content::WebRtcLocalAudioTrack::Capture
+...
+*!content::SpeechRecognitionAudioSinkTest_*_Test::TestBody
+

tools/valgrind/memcheck/suppressions.txt

@@ -3478,3 +3478,11 @@
    fun:_ZN7content30SpeechRecognitionAudioSinkTest35AssertConsumptionForAudioParametersEiiiij
    fun:_ZN7content62SpeechRecognitionAudioSinkTest_RecognizerNotifiedOnSocket_Test8TestBodyEv
 }
+{
+   bug_422472b
+   Memcheck:Uninitialized
+   ...
+   fun:_ZN7content31MediaStreamAudioLevelCalculator9CalculateEPKsii
+   ...
+   fun:_ZN7content62SpeechRecognitionAudioSinkTest_RecognizerNotifiedOnSocket_Test8TestBodyEv
+}