build: move libcc patches to electron repo (#14104)

In the GN build, libchromiumcontent is no longer a distinct library, but
merely a container for a set of scripts and patches. Maintaining those
patches in a separate repository is tedious and error-prone, so merge
them into the main repo.

Once this is merged and GN is the default way to build Electron, the
libchromiumcontent repository can be archived.

patches/common/chromium/webgl_context_attributes.patch

@@ -0,0 +1,111 @@
+diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
+index 0affacaa0294..0c321d51364d 100644
+--- a/content/renderer/renderer_blink_platform_impl.cc
++++ b/content/renderer/renderer_blink_platform_impl.cc
+@@ -1136,8 +1136,10 @@ RendererBlinkPlatformImpl::CreateOffscreenGraphicsContext3DProvider(
+   attributes.sample_buffers = 0;
+   attributes.bind_generates_resource = false;
+   attributes.enable_raster_interface = web_attributes.enable_raster_interface;
+-  // Prefer discrete GPU for WebGL.
+-  attributes.gpu_preference = gl::PreferDiscreteGpu;
++
++  attributes.gpu_preference = web_attributes.prefer_integrated_gpu
++      ? gl::PreferIntegratedGpu
++      : gl::PreferDiscreteGpu;
+ 
+   attributes.fail_if_major_perf_caveat =
+       web_attributes.fail_if_major_performance_caveat;
+diff --git a/third_party/blink/renderer/core/html/canvas/canvas_context_creation_attributes_core.h b/third_party/blink/renderer/core/html/canvas/canvas_context_creation_attributes_core.h
+index ca4543a10e69..a1f5e5c9f906 100644
+--- a/third_party/blink/renderer/core/html/canvas/canvas_context_creation_attributes_core.h
++++ b/third_party/blink/renderer/core/html/canvas/canvas_context_creation_attributes_core.h
+@@ -30,6 +30,7 @@ class CORE_EXPORT CanvasContextCreationAttributesCore {
+   String pixel_format = "8-8-8-8";
+   bool premultiplied_alpha = true;
+   bool preserve_drawing_buffer = false;
++  String power_preference = "default";
+   bool stencil = false;
+ 
+   // This attribute is of type XRDevice, defined in modules/xr/XRDevice.h
+diff --git a/third_party/blink/renderer/modules/canvas/htmlcanvas/canvas_context_creation_attributes_module.idl b/third_party/blink/renderer/modules/canvas/htmlcanvas/canvas_context_creation_attributes_module.idl
+index 7419bb20d316..5b04af00fab4 100644
+--- a/third_party/blink/renderer/modules/canvas/htmlcanvas/canvas_context_creation_attributes_module.idl
++++ b/third_party/blink/renderer/modules/canvas/htmlcanvas/canvas_context_creation_attributes_module.idl
+@@ -28,6 +28,12 @@ enum CanvasPixelFormat {
+     "float16",
+ };
+ 
++enum CanvasPowerPreference {
++    "default",
++    "low-power",
++    "high-performance",
++};
++
+ [PermissiveDictionaryConversion]
+ dictionary CanvasContextCreationAttributesModule {
+     // This is an experimental feature, but it is not hidden behind a flag in
+@@ -47,6 +47,7 @@ dictionary CanvasContextCreationAttributesModule {
+     boolean antialias = true;
+     boolean premultipliedAlpha = true;
+     boolean preserveDrawingBuffer = false;
++    CanvasPowerPreference powerPreference = "default";
+     boolean failIfMajorPerformanceCaveat = false;
+     [OriginTrialEnabled=WebXR] XRDevice compatibleXRDevice = null;
+ };
+diff --git a/third_party/blink/renderer/modules/webgl/webgl_context_attribute_helpers.cc b/third_party/blink/renderer/modules/webgl/webgl_context_attribute_helpers.cc
+index 332fa9fb0547..e8fae4b01c39 100644
+--- a/third_party/blink/renderer/modules/webgl/webgl_context_attribute_helpers.cc
++++ b/third_party/blink/renderer/modules/webgl/webgl_context_attribute_helpers.cc
+@@ -18,6 +18,7 @@ WebGLContextAttributes ToWebGLContextAttributes(
+   result.setAntialias(attrs.antialias);
+   result.setPremultipliedAlpha(attrs.premultiplied_alpha);
+   result.setPreserveDrawingBuffer(attrs.preserve_drawing_buffer);
++  result.setPowerPreference(attrs.power_preference);
+   result.setFailIfMajorPerformanceCaveat(
+       attrs.fail_if_major_performance_caveat);
+   result.setCompatibleXRDevice(
+@@ -30,6 +30,7 @@ Platform::ContextAttributes ToPlatformContextAttributes(
+     unsigned web_gl_version,
+     bool support_own_offscreen_surface) {
+   Platform::ContextAttributes result;
++  result.prefer_integrated_gpu = attrs.power_preference == "low-power";
+   result.fail_if_major_performance_caveat =
+       attrs.fail_if_major_performance_caveat;
+   result.context_type = web_gl_version == 2 ? Platform::kWebGL2ContextType
+diff --git a/third_party/blink/renderer/modules/webgl/webgl_context_attributes.idl b/third_party/blink/renderer/modules/webgl/webgl_context_attributes.idl
+index 180673be9bd0..0af29cbc9402 100644
+--- a/third_party/blink/renderer/modules/webgl/webgl_context_attributes.idl
++++ b/third_party/blink/renderer/modules/webgl/webgl_context_attributes.idl
+@@ -26,6 +26,12 @@
+ 
+ // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.2
+ 
++enum WebGLPowerPreference {
++    "default",
++    "low-power",
++    "high-performance",
++};
++
+ dictionary WebGLContextAttributes {
+     boolean alpha = true;
+     boolean depth = true;
+@@ -33,6 +33,7 @@ dictionary WebGLContextAttributes {
+     boolean antialias = true;
+     boolean premultipliedAlpha = true;
+     boolean preserveDrawingBuffer = false;
++    WebGLPowerPreference powerPreference = "default";
+     boolean failIfMajorPerformanceCaveat = false;
+     [OriginTrialEnabled=WebXR] XRDevice compatibleXRDevice = null;
+ };
+diff --git a/third_party/blink/public/platform/platform.h b/third_party/blink/public/platform/platform.h
+index d4948345246e..bc277ba6aa5f 100644
+--- a/third_party/blink/public/platform/platform.h
++++ b/third_party/blink/public/platform/platform.h
+@@ -522,6 +522,7 @@ class BLINK_PLATFORM_EXPORT Platform {
+     kGLES3ContextType,   // GLES 3.0 context
+   };
+   struct ContextAttributes {
++    bool prefer_integrated_gpu = false;
+     bool fail_if_major_performance_caveat = false;
+     ContextType context_type = kGLES2ContextType;
+     // Offscreen contexts usually share a surface for the default frame buffer