Re-land "Remove <(webrtc_root) from source file entries."

Changes differing from https://webrtc-codereview.appspot.com/37859004:
* I put the include_tests==1 stuff of audio_coding.gypi in its
  own audio_coding_tests.gypi file, including the Android and isolate
  targets which were incorrectly located in the previous CL
* I moved the bwe utilities in remote_bitrate_estimator.gypi
  into include_tests==1 since they depend on test.gyp after I
  cleaned up the duplicated inclusion of rtp_file_reader.cc

R=stefan@webrtc.org
TBR=tina.legrand@webrtc.org
TESTED=Passing gyp and compile using:
webrtc/build/gyp_webrtc -Dinclude_tests=1
webrtc/build/gyp_webrtc -Dinclude_tests=0
I also setup a Chromium checkout with my checkout mounted in
third_party/webrtc and ran build/gyp_chromium successfully.

BUG=4185

Review URL: https://webrtc-codereview.appspot.com/33159004

Cr-Commit-Position: refs/heads/master@{#8205}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8205 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_coding/audio_codec_speed_tests.isolate

@@ -0,0 +1,33 @@
+# Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+{
+  'conditions': [
+    ['OS=="linux" or OS=="mac" or OS=="win" or OS=="android"', {
+      'variables': {
+        'files': [
+          '<(DEPTH)/resources/audio_coding/music_stereo_48kHz.pcm',
+          '<(DEPTH)/resources/audio_coding/speech_mono_16kHz.pcm',
+          '<(DEPTH)/resources/audio_coding/speech_mono_32_48kHz.pcm',
+        ],
+      },
+    }],
+    ['OS=="linux" or OS=="mac" or OS=="win"', {
+      'variables': {
+        'command': [
+          '<(DEPTH)/testing/test_env.py',
+          '<(PRODUCT_DIR)/audio_codec_speed_tests<(EXECUTABLE_SUFFIX)',
+        ],
+        'files': [
+          '<(DEPTH)/DEPS',
+          '<(DEPTH)/testing/test_env.py',
+          '<(PRODUCT_DIR)/audio_codec_speed_tests<(EXECUTABLE_SUFFIX)',
+        ],
+      },
+    }],
+  ],
+}