Don't attempt playback if not possible

chrome/browser/media/encrypted_media_browsertest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/windows_version.h"
 #include "chrome/browser/media/media_browsertest.h"
@@ skipping 398 matching lines @@
                           const std::string& media_type) {
     RunSimpleEncryptedMediaTest(encrypted_media,
                                 media_type,
                                 CurrentKeySystem(),
                                 CurrentSourceType(),
                                 CurrentEmeVersion());
   }
 
   void TestMultiplePlayback(const std::string& encrypted_media,
                             const std::string& media_type) {
+    DCHECK(IsPlayBackPossible(CurrentKeySystem()));
     RunEncryptedMediaTest(kDefaultEmePlayer, encrypted_media, media_type,
                           CurrentKeySystem(), CurrentSourceType(),
                           CurrentEmeVersion(), kNoSessionToLoad, false,
                           PlayTwice::YES, kEnded);
   }
 
   void RunInvalidResponseTest() {
     RunEncryptedMediaTest(kDefaultEmePlayer, "bear-320x240-av_enc-av.webm",
                           kWebMAudioVideo, CurrentKeySystem(),
                           CurrentSourceType(), CurrentEmeVersion(),
@@ skipping 139 matching lines @@
 
 IN_PROC_BROWSER_TEST_P(EncryptedMediaTest, Playback_VideoAudio_WebM_Opus) {
   TestSimplePlayback("bear-320x240-opus-av_enc-av.webm", kWebMAudioVideo);
 }
 
 IN_PROC_BROWSER_TEST_P(EncryptedMediaTest, Playback_VideoClearAudio_WebM_Opus) {
   TestSimplePlayback("bear-320x240-opus-av_enc-v.webm", kWebMAudioVideo);
 }
 
 IN_PROC_BROWSER_TEST_P(EncryptedMediaTest, Playback_Multiple_VideoAudio_WebM) {
+  if (!IsPlayBackPossible(CurrentKeySystem())) {
+    DVLOG(0) << "Skipping test - Playback_Multiple test requires playback.";
+    return;
+  }
   TestMultiplePlayback("bear-320x240-av_enc-av.webm", kWebMAudioVideo);
 }
 
 IN_PROC_BROWSER_TEST_P(EncryptedMediaTest, InvalidResponseKeyError) {
   RunInvalidResponseTest();
 }
 
 IN_PROC_BROWSER_TEST_P(EncryptedMediaTest, ConfigChangeVideo) {
   if (CurrentSourceType() != MSE || !IsMSESupported()) {
     DVLOG(0) << "Skipping test - ConfigChange test requires MSE.";
@@ skipping 121 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(ECKPrefixedEncryptedMediaTest, LoadLoadableSession) {
   TestPlaybackCase(kLoadableSession, kEnded);
 }
 
 IN_PROC_BROWSER_TEST_F(ECKPrefixedEncryptedMediaTest, LoadUnknownSession) {
   // TODO(xhwang): Add a specific error for this failure, e.g. kSessionNotFound.
   TestPlaybackCase(kUnknownSession, kEmeKeyError);
 }
 #endif  // defined(ENABLE_PEPPER_CDMS)