Revert "Switch cc_unittests/viz_unittests to SwANGLE"

This reverts commit 28c5ad9b.

Reason for revert: suspect culprit for PrecisionSamplerShadersCompile/PrecisionSamplerShaderPixelTest.ShadersCompile/* failures on linux-tests-dbg: https://ci.chromium.org/p/chromium/builders/ci/Linux%20Tests%20%28dbg%29%281%29/93470

Original change's description:
> Switch cc_unittests/viz_unittests to SwANGLE
>
> This cl changes the software backend used for
> running viz_unittests and cc_unittests from
> SwiftShader GL to SwANGLE (ANGLE on SwiftShader
> Vulkan). Other tests suites may be affected.
>
> From this cl, performance expectations for test
> runs will likely change. For example, cc_unittests
> appears to run faster, while viz_unittests and
> views_unittests appear to run slower. Note that
> this is still using the validating command decoder,
> and once the OOP Raster tests can run on the
> passthrough command decoder, we'll be able to use
> it and gain some performance on all these test runs.
>
> Bug: chromium:1060139
> Change-Id: Ia243f05f3e9f54dc6f6dfaa3041021fc28818b2f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532042
> Commit-Queue: Alexis Hétu <sugoi@chromium.org>
> Reviewed-by: weiliangc <weiliangc@chromium.org>
> Reviewed-by: Kenneth Russell <kbr@chromium.org>
> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
> Cr-Commit-Position: refs/heads/master@{#834246}

TBR=sugoi@chromium.org,kbr@chromium.org,weiliangc@chromium.org,khushalsagar@chromium.org,jonahr@google.com,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com,sugoi@google.com

Change-Id: I815d610741c258a66dc360b2d302d2f663a3bf4c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1060139
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577957Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834373}

cc/test/layer_tree_test.cc

@@ -53,7 +53,6 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "ui/base/ui_base_features.h"
 #include "ui/gfx/geometry/size_conversions.h"
-#include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_switches.h"
 
 namespace cc {
@@ -971,13 +970,6 @@ void LayerTreeTest::RealEndTest() {
   base::RunLoop::QuitCurrentWhenIdleDeprecated();
 }
 
-bool LayerTreeTest::use_swangle() const {
-  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  return (gl::GetGLImplementation() == gl::kGLImplementationEGLANGLE) &&
-         (command_line->GetSwitchValueASCII(::switches::kUseANGLE) ==
-          gl::kANGLEImplementationSwiftShaderName);
-}
-
 void LayerTreeTest::DispatchAddNoDamageAnimation(
     Animation* animation_to_receive_animation,
     double animation_duration) {

cc/test/layer_tree_test.h

@@ -229,7 +229,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
     return false;
 #endif
   }
-  bool use_swangle() const;
 
   const viz::RendererType renderer_type_;
 

cc/trees/layer_tree_host_pixeltest_filters.cc

@@ -610,11 +610,7 @@ TEST_P(LayerTreeHostFiltersPixelTest, ImageFilterScaled) {
 
   RunPixelTest(
       background,
-      base::FilePath(
-          (use_swangle() || use_skia_vulkan())
-              ? FILE_PATH_LITERAL("backdrop_filter_on_scaled_layer_.png")
-              : FILE_PATH_LITERAL(
-                    "backdrop_filter_on_scaled_layer_legacy_swiftshader_.png"))
+      base::FilePath(FILE_PATH_LITERAL("backdrop_filter_on_scaled_layer_.png"))
           .InsertBeforeExtensionASCII(GetRendererSuffix()));
 }
 
@@ -728,11 +724,7 @@ TEST_P(LayerTreeHostFiltersPixelTest, ImageRenderSurfaceScaled) {
 
   RunPixelTest(
       background,
-      base::FilePath(
-          (use_swangle() || use_skia_vulkan())
-              ? FILE_PATH_LITERAL("scaled_render_surface_layer_.png")
-              : FILE_PATH_LITERAL(
-                    "scaled_render_surface_layer_legacy_swiftshader_.png"))
+      base::FilePath(FILE_PATH_LITERAL("scaled_render_surface_layer_.png"))
           .InsertBeforeExtensionASCII(GetRendererSuffix()));
 }
 

cc/trees/layer_tree_host_pixeltest_scrollbars.cc

@@ -173,22 +173,14 @@ TEST_P(LayerTreeHostScrollbarsPixelTest, MAYBE_HugeTransformScale) {
   scale_transform.Scale(scale, scale);
   layer->SetTransform(scale_transform);
 
-  if (use_swangle() || use_skia_vulkan() ||
-      renderer_type_ == viz::RendererType::kSkiaGL ||
+  if (renderer_type_ == viz::RendererType::kSkiaGL ||
       renderer_type_ == viz::RendererType::kSkiaDawn)
     pixel_comparator_ = std::make_unique<FuzzyPixelOffByOneComparator>(true);
 
-  RunPixelTest(
-      background,
-      base::FilePath(
-          use_swangle()
-              ? (use_skia_vulkan() ? FILE_PATH_LITERAL("spiral_64_scale_vk.png")
-                                   : FILE_PATH_LITERAL("spiral_64_scale.png"))
-              : (use_skia_vulkan()
-                     ? FILE_PATH_LITERAL(
-                           "spiral_64_scale_legacy_swiftshader_vk.png")
-                     : FILE_PATH_LITERAL(
-                           "spiral_64_scale_legacy_swiftshader.png"))));
+  RunPixelTest(background,
+               use_skia_vulkan()
+                   ? base::FilePath(FILE_PATH_LITERAL("spiral_64_scale_vk.png"))
+                   : base::FilePath(FILE_PATH_LITERAL("spiral_64_scale.png")));
 }
 
 class LayerTreeHostOverlayScrollbarsPixelTest

ui/gl/test/gl_surface_test_support.cc

@@ -66,30 +66,9 @@ void InitializeOneOffHelper(bool init_extensions) {
   DCHECK(!allowed_impls.empty());
 
   GLImplementation impl = allowed_impls[0];
-  if (use_software_gl) {
+  if (use_software_gl)
     impl = gl::GetSoftwareGLImplementation();
 
-#if !defined(OS_ANDROID) && !defined(OS_FUCHSIA)
-#if defined(USE_OZONE)
-    if (!features::IsUsingOzonePlatform())
-#endif
-    {
-      // If ANGLE is available use it with SwiftShader Vulkan instead of using
-      // SwiftShader GL
-      for (auto i : allowed_impls) {
-        if (i == kGLImplementationEGLANGLE) {
-          impl = kGLImplementationEGLANGLE;
-          base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-              switches::kUseANGLE, kANGLEImplementationSwiftShaderName);
-          base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-              switches::kUseCmdDecoder, kCmdDecoderValidatingName);
-          break;
-        }
-      }
-    }
-#endif
-  }
-
   DCHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseGL))
       << "kUseGL has not effect in tests";