commit 06c9513ba20f85908b376865d0777633a29740ea
author Stephen McGruer <smcgruer@chromium.org> Wed Jun 26 00:31:50 2019
committer Commit Bot <commit-bot@chromium.org> Wed Jun 26 00:31:50 2019
tree 55c0d676a220e348c1bb49eb08dda86e46142bb0
parent b75791185133bde02d01a078272f0e1de10950db

Add command line switch to force prefers-reduced-motion

This enables users who are on platforms where we do not yet support
prefers-reduced-motion (primarily Linux) or where the user does not have
control over the system settings to launch Chrome in the
prefers-reduced-motion mode.

Bug: 929310
Change-Id: I1e6c1175911b769198aeb3a4f0e00da3ed9f3f80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1671668
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672344}

ui/gfx/animation/BUILD.gn

diff --git a/ui/gfx/animation/BUILD.gn b/ui/gfx/animation/BUILD.gn
index 8e3d773..81610e2 100644
--- a/ui/gfx/animation/BUILD.gn
+++ b/ui/gfx/animation/BUILD.gn
@@ -59,6 +59,7 @@
     "//skia",
     "//ui/gfx:geometry_skia",
     "//ui/gfx:gfx_export",
+    "//ui/gfx:gfx_switches",
     "//ui/gfx/geometry",
   ]
 

ui/gfx/animation/animation.cc

diff --git a/ui/gfx/animation/animation.cc b/ui/gfx/animation/animation.cc
index 92ae9cbf..096ed51 100644
--- a/ui/gfx/animation/animation.cc
+++ b/ui/gfx/animation/animation.cc
@@ -6,12 +6,14 @@
 
 #include <memory>
 
+#include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "build/build_config.h"
 #include "ui/gfx/animation/animation_container.h"
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/gfx/animation/tween.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/switches.h"
 
 namespace gfx {
 
@@ -139,6 +141,10 @@
 
 // static
 bool Animation::PrefersReducedMotion() {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kForcePrefersReducedMotion)) {
+    return true;
+  }
   if (!prefers_reduced_motion_)
     UpdatePrefersReducedMotion();
   return *prefers_reduced_motion_;

ui/gfx/switches.cc

diff --git a/ui/gfx/switches.cc b/ui/gfx/switches.cc
index 189e147e..ba3dbf23 100644
--- a/ui/gfx/switches.cc
+++ b/ui/gfx/switches.cc
@@ -12,6 +12,10 @@
 const char kDisableFontSubpixelPositioning[] =
     "disable-font-subpixel-positioning";
 
+// Forces whether the user desires reduced motion, regardless of system
+// settings.
+const char kForcePrefersReducedMotion[] = "force-prefers-reduced-motion";
+
 // Run in headless mode, i.e., without a UI or display server dependencies.
 const char kHeadless[] = "headless";
 

ui/gfx/switches.h

diff --git a/ui/gfx/switches.h b/ui/gfx/switches.h
index c95989ae..1f0e6338 100644
--- a/ui/gfx/switches.h
+++ b/ui/gfx/switches.h
@@ -12,6 +12,8 @@
 
 GFX_SWITCHES_EXPORT extern const char kDisableFontSubpixelPositioning[];
 
+GFX_SWITCHES_EXPORT extern const char kForcePrefersReducedMotion[];
+
 GFX_SWITCHES_EXPORT extern const char kHeadless[];
 
 GFX_SWITCHES_EXPORT extern const char kEnableNativeGpuMemoryBuffers[];