Set the chromium_code GYP variable.

When building in the Chromium tree, chromium_code is necessary to apply
Chromium’s build/filename_rules.gypi. Crashpad’s build depends on these
rules. chromium_code also enables a high warning level, which is
desirable for Crashpad.

BUG=crashpad:12
R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/986873002

build/crashpad.gypi

@@ -0,0 +1,23 @@
+# Copyright 2015 The Crashpad Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+{
+  'variables': {
+    # When building as a part of Chromium, this variable sets up the build to
+    # treat Crashpad as Chromium code. This enables warnings at an appropriate
+    # level and applies Chromium’s build/filename_rules.gypi. In a standalone
+    # build, this variable has no effect.
+    'chromium_code': 1,
+  },
+}

client/client.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'targets': [
     {
       'target_name': 'client',

compat/compat.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'targets': [
     {
       'target_name': 'compat',

handler/handler.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'conditions': [
     ['OS=="mac"', {
       'targets': [

minidump/minidump.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'targets': [
     {
       'target_name': 'minidump',

snapshot/snapshot.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'targets': [
     {
       'target_name': 'snapshot',

tools/tools.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'conditions': [
     ['OS=="mac"', {
       'variables': {

util/util.gyp

@@ -13,6 +13,9 @@
 # limitations under the License.
 
 {
+  'includes': [
+    '../build/crashpad.gypi',
+  ],
   'targets': [
     {
       'target_name': 'util',