Remove the rtc_relative_path GYP variable and similar defines

This is a reland of https://codereview.webrtc.org/1903553003/ but with
the SRTP changes removed, since they're needed downstream.

The defines that can be used to alter the include paths for Expat and gtest
are no longer needed in WebRTC or Chromium. Remove them to simplify GYP.

Removed defines:
EXPAT_RELATIVE_PATH
GTEST_RELATIVE_PATH

They're all set in the Chromium build so this shouldn't affect Chromium:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/libjingle/libjingle.gyp

BUG=webrtc:4256
NOTRY=True
NOPRESUBMIT=True
TBR=perkj@webrtc.org

Review-Url: https://codereview.webrtc.org/1925733002
Cr-Commit-Position: refs/heads/master@{#12536}

webrtc/base/base_tests.gyp

@@ -23,19 +23,11 @@
         'testechoserver.h',
         'testutils.h',
       ],
-      'defines': [
-        'GTEST_RELATIVE_PATH',
-      ],
       'dependencies': [
         'base.gyp:rtc_base',
         '<(DEPTH)/testing/gtest.gyp:gtest',
         '<(webrtc_root)/test/test.gyp:field_trial',
       ],
-      'direct_dependent_settings': {
-        'defines': [
-          'GTEST_RELATIVE_PATH',
-        ],
-      },
       'export_dependent_settings': [
         '<(DEPTH)/testing/gtest.gyp:gtest',
       ],

webrtc/base/gunit.h

@@ -13,11 +13,7 @@
 
 #include "webrtc/base/logging.h"
 #include "webrtc/base/thread.h"
-#if defined(GTEST_RELATIVE_PATH)
 #include "testing/gtest/include/gtest/gtest.h"
-#else
-#include "testing/base/public/gunit.h"
-#endif
 
 // Wait until "ex" is true, or "timeout" expires.
 #define WAIT(ex, timeout)                                                     \

webrtc/base/gunit_prod.h

@@ -15,10 +15,7 @@
 // Android doesn't use gtest at all, so anything that relies on gtest should
 // check this define first.
 #define NO_GTEST
-#elif defined (GTEST_RELATIVE_PATH)
-#include "gtest/gtest_prod.h"
-#else
-#include "testing/base/gunit_prod.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"
 #endif
 
 #endif  // WEBRTC_BASE_GUNIT_PROD_H_

webrtc/build/common.gypi

@@ -64,7 +64,6 @@
     'webrtc_vp9_dir%': '<(webrtc_vp9_dir)',
     'include_ilbc%': '<(include_ilbc)',
     'include_opus%': '<(include_opus)',
-    'rtc_relative_path%': 1,
     'external_libraries%': '0',
     'json_root%': '<(DEPTH)/third_party/jsoncpp/source/include/',
     # openssl needs to be defined or gyp will complain. Is is only used when
@@ -238,9 +237,6 @@
            '<!@(pkg-config --cflags dbus-glib-1)',
          ],
       }],
-      ['rtc_relative_path==1', {
-        'defines': ['EXPAT_RELATIVE_PATH',],
-      }],
       ['os_posix==1', {
         'configurations': {
           'Debug_Base': {

webrtc/libjingle/xmllite/xmlbuilder.h

@@ -16,11 +16,7 @@
 #include "webrtc/libjingle/xmllite/xmlparser.h"
 #include "webrtc/base/scoped_ptr.h"
 
-#ifdef EXPAT_RELATIVE_PATH
 #include "expat.h"
-#else
-#include "third_party/expat/v2_0_1/Source/lib/expat.h"
-#endif  // EXPAT_RELATIVE_PATH
 
 namespace buzz {
 

webrtc/libjingle/xmllite/xmlparser.h

@@ -14,11 +14,7 @@
 #include <string>
 
 #include "webrtc/libjingle/xmllite/xmlnsstack.h"
-#ifdef EXPAT_RELATIVE_PATH
 #include "expat.h"
-#else
-#include "third_party/expat/v2_0_1/Source/lib/expat.h"
-#endif  // EXPAT_RELATIVE_PATH
 
 struct XML_ParserStruct;
 typedef struct XML_ParserStruct* XML_Parser;

webrtc/libjingle/xmpp/xmppstanzaparser.cc

@@ -13,11 +13,7 @@
 #include "webrtc/libjingle/xmllite/xmlelement.h"
 #include "webrtc/libjingle/xmpp/constants.h"
 #include "webrtc/base/common.h"
-#ifdef EXPAT_RELATIVE_PATH
 #include "expat.h"
-#else
-#include "third_party/expat/v2_0_1/Source/lib/expat.h"
-#endif
 
 namespace buzz {
 

webrtc/webrtc_tests.gypi

@@ -271,9 +271,6 @@
         'base/socketaddress_unittest.cc',
         'base/virtualsocket_unittest.cc',
       ],
-      'defines': [
-        'GTEST_RELATIVE_PATH',
-      ],
       'dependencies': [
         '<(DEPTH)/testing/gtest.gyp:gtest',
         'base/base.gyp:rtc_base',