Setup git submodules for all sources included from chromium

Some of the modules was semi-setup when copied from chromium.

With submodule setup, the user may use git submodule init and update
to update the submodules.

Change-Id: Ief0899c1567cd2be9a55710f7f81c0eb74461f50

.gitignore

@@ -4,11 +4,8 @@
 .pydevproject
 .repo
 .settings
-/base/
-/build/
 /docs/
 /out/
-/third_party/gold/
 # Ignore llvm-build. This is only when you are using clang. Address Sanitizer
 # requires clang.
 /third_party/llvm-build/

.gitmodules

@@ -0,0 +1,25 @@
+[submodule "base"]
+	path = base
+	url = https://chromium.googlesource.com/chromium/src/base.git
+[submodule "build"]
+	path = build
+	url = https://chromium.googlesource.com/chromium/src/build.git
+	ignore = untracked
+[submodule "testing/gmock"]
+	path = testing/gmock
+	url = https://chromium.googlesource.com/external/googlemock.git
+[submodule "testing/gtest"]
+	path = testing/gtest
+	url = https://chromium.googlesource.com/external/googletest.git
+[submodule "third_party/gold"]
+	path = third_party/gold
+	url = https://chromium.googlesource.com/chromium/deps/gold.git
+[submodule "third_party/icu"]
+	path = third_party/icu
+	url = https://chromium.googlesource.com/chromium/deps/icu46.git
+[submodule "third_party/openssl"]
+	path = third_party/openssl
+	url = https://chromium.googlesource.com/chromium/deps/openssl.git
+[submodule "tools/gyp"]
+	path = tools/gyp
+	url = https://chromium.googlesource.com/external/gyp.git

base

@@ -0,0 +1 @@
+Subproject commit 44f298322368aff31c5a697a2659bd52a5175541

build

@@ -0,0 +1 @@
+Subproject commit 3f959aa1388b6308e66cae89adee01ae135f1c04

third_party/gold

@@ -0,0 +1 @@
+Subproject commit b471bdbb6e7c0ab8c5f105cc1489177fa4105778