Make fake audio file playback loop by default.

media/audio/fake_audio_input_stream.cc

Index: media/audio/fake_audio_input_stream.cc
diff --git a/media/audio/fake_audio_input_stream.cc b/media/audio/fake_audio_input_stream.cc
index af4f7e1b2761a6f25bde438f5d486c29400e54ba..48ca3e55534189dc55d76aade213635eed50b767 100644
--- a/media/audio/fake_audio_input_stream.cc
+++ b/media/audio/fake_audio_input_stream.cc
@@ -10,6 +10,7 @@
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
+#include "base/strings/string_split.h"
 #include "base/time/time.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/audio/simple_sources.h"
@@ -109,14 +110,24 @@ std::unique_ptr<AudioSourceCallback> FakeAudioInputStream::ChooseSource() {
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kUseFileForFakeAudioCapture)) {
-    base::FilePath path_to_wav_file =
-        base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
+    base::CommandLine::StringType switch_value =
+        base::CommandLine::ForCurrentProcess()->GetSwitchValueNative(
             switches::kUseFileForFakeAudioCapture);
-    CHECK(!path_to_wav_file.empty())
-        << "You must pass the file to use as argument to --"
-        << switches::kUseFileForFakeAudioCapture << ".";
-
-    return base::WrapUnique(new FileSource(params_, path_to_wav_file));
+    base::CommandLine::StringVector parameters =
+        base::SplitString(switch_value, FILE_PATH_LITERAL("%"),
+                          base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+    CHECK(parameters.size() > 0) << "You must pass <file>[%noloop] to  --"
+                                 << switches::kUseFileForFakeAudioCapture
+                                 << ".";
+    base::FilePath path_to_wav_file = base::FilePath(parameters[0]);
+    bool looping = true;
+    if (parameters.size() == 2) {
+      CHECK(parameters[1] == FILE_PATH_LITERAL("noloop"))
+          << "Unknown parameter " << parameters[1] << " to "
+          << switches::kUseFileForFakeAudioCapture << ".";
+      looping = false;
+    }
+    return base::WrapUnique(new FileSource(params_, path_to_wav_file, looping));
   }
   return base::WrapUnique(new BeepingSource(params_));
 }