Reduce the runtime of some ACM tests in modules_tests

webrtc/modules/audio_coding/test/TestAllCodecs.cc

Index: webrtc/modules/audio_coding/test/TestAllCodecs.cc
diff --git a/webrtc/modules/audio_coding/test/TestAllCodecs.cc b/webrtc/modules/audio_coding/test/TestAllCodecs.cc
index 21ce7c11aa8749b2bb0fbda94301bb927c5b3880..7da844983595cb13897afb32ab8323af2af1bb09 100644
--- a/webrtc/modules/audio_coding/test/TestAllCodecs.cc
+++ b/webrtc/modules/audio_coding/test/TestAllCodecs.cc
@@ -16,6 +16,7 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 
+#include "webrtc/base/checks.h"
 #include "webrtc/common_types.h"
 #include "webrtc/engine_configurations.h"
 #include "webrtc/modules/audio_coding/include/audio_coding_module.h"
@@ -422,8 +423,13 @@ void TestAllCodecs::Run(TestPack* channel) {
   uint32_t timestamp_diff;
   channel->reset_payload_size();
   int error_count = 0;
-
   int counter = 0;
+  static const int kTestLengthMs = 500;
+  const int test_length_blocks = rtc::CheckedDivExact(kTestLengthMs, 10);
+  infile_a_.SetNum10MsBlocksToRead(test_length_blocks);

[ivoc, 2015/12/10 12:23:57]

You could consider hardcoding the number of blocks here as below, and explain in
a comment.

[hlundin-webrtc, 2015/12/10 12:49:59]

Done.

+  // Fast-forward 1 second (100 blocks) since the file starts with silence.
+  infile_a_.FastForward(100);
+
   while (!infile_a_.EndOfFile()) {
     // Add 10 msec to ACM.
     infile_a_.Read10MsData(audio_frame);