Add third_party/abseil-cpp to ANGLE

1. Add third_party/abseil-cpp to DEPS so it can be used in ANGLE.
2. Add abseil directory to ANGLE overrides.
3. Add third_party/abseil-cpp to .gitignore.
4. Add third_party/abseil-cpp to roll_chromium_deps.py so it's
auto-rolled periodically.

Bug: angleproject:4873
Change-Id: Ic158bba844e88ec90ac56a2f8c817168c4bea17f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2321734
Commit-Queue: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>

.gitignore

@@ -29,6 +29,7 @@
 .git_cl_description_backup
 /src/tests/third_party/gles_conformance_tests
 /testing
+/third_party/abseil-cpp
 /third_party/android_ndk
 /third_party/catapult
 /third_party/cherry

DEPS

@@ -117,6 +117,11 @@ deps = {
     'condition': 'not build_with_chromium',
   },
 
+  'third_party/abseil-cpp': {
+    'url': '{chromium_git}/chromium/src/third_party/abseil-cpp@24b0f4945201170f3d051f2b174966ae1f615756',
+    'condition': 'not build_with_chromium',
+  },
+
   'third_party/android_ndk': {
     'url': '{chromium_git}/android_ndk.git@27c0a8d090c666a50e40fceb4ee5b40b1a2d3f87',
     'condition': 'checkout_android and not build_with_chromium',
@@ -140,15 +145,6 @@ deps = {
     'condition': 'dummy_checkout_chromium',
   },
 
-  'third_party/vulkan_memory_allocator': {
-    'url': '{chromium_git}/external/github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator@065e739079d9d58bef28ccd793cbf512261f09ed',
-    'condition': 'not build_with_chromium',
-  },
-
-  'third_party/VK-GL-CTS/src': {
-    'url': '{chromium_git}/external/github.com/KhronosGroup/VK-GL-CTS@{vk_gl_cts_revision}',
-  },
-
   'third_party/fuchsia-sdk': {
     'url': '{chromium_git}/chromium/src/third_party/fuchsia-sdk.git@1785f0ac8e1fe81cb25e260acbe7de8f62fa3e44',
     'condition': 'checkout_fuchsia and not build_with_chromium',
@@ -247,6 +243,10 @@ deps = {
     'condition': 'not build_with_chromium',
   },
 
+  'third_party/VK-GL-CTS/src': {
+    'url': '{chromium_git}/external/github.com/KhronosGroup/VK-GL-CTS@{vk_gl_cts_revision}',
+  },
+
   'third_party/vulkan-headers/src': {
     'url': '{chromium_git}/external/github.com/KhronosGroup/Vulkan-Headers@{vulkan_headers_revision}',
   },
@@ -255,6 +255,11 @@ deps = {
     'url': '{chromium_git}/external/github.com/KhronosGroup/Vulkan-Loader@{vulkan_loader_revision}',
   },
 
+  'third_party/vulkan_memory_allocator': {
+    'url': '{chromium_git}/external/github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator@065e739079d9d58bef28ccd793cbf512261f09ed',
+    'condition': 'not build_with_chromium',
+  },
+
   'third_party/vulkan-tools/src': {
     'url': '{chromium_git}/external/github.com/KhronosGroup/Vulkan-Tools@{vulkan_tools_revision}',
   },

build_overrides/angle.gni

@@ -9,6 +9,7 @@ angle_root = "//"
 angle_has_build = true
 
 # Overrides for ANGLE's dependencies
+angle_abseil_cpp_dir = "//third_party/abseil-cpp"
 angle_glslang_dir = "//third_party/glslang/src"
 angle_googletest_dir = "//third_party/googletest/src"
 angle_jsoncpp_dir = "//third_party/jsoncpp"

scripts/roll_chromium_deps.py

@@ -34,6 +34,7 @@ ANGLE_CHROMIUM_DEPS = [
     'build',
     'buildtools',
     'testing',
+    'third_party/abseil-cpp',
     'third_party/libjpeg_turbo',
     'third_party/nasm',
     'third_party/Python-Markdown',