Fix vr_shell shader not compiling on Samsung phones.

chrome/browser/android/vr_shell/vr_shell_renderer.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/vr_shell/vr_shell_renderer.h"
 
 #include "chrome/browser/android/vr_shell/vr_gl_util.h"
 
 namespace {
 
@@ skipping 133 matching lines @@
             mediump float hole_alpha =
                 clamp((r - hole_radius) / color_feather_radius, 0.0, 1.0);
 
             mediump float black_radius = mid_ring_end * ring_diameter;
             mediump float black_feather =
                 1.0 / (ring_diameter * 0.5 - black_radius);
             mediump float black_alpha_factor =
                 mid_ring_opacity * (1.0 - (r - black_radius) * black_feather);
             mediump float alpha = clamp(
                 min(hole_alpha, max(color1, black_alpha_factor)), 0.0, 1.0);
-            vec3 color_rgb = color1 * color.xyz;
+            lowp vec3 color_rgb = color1 * color.xyz;
             gl_FragColor = vec4(color_rgb, color.w * alpha);
           });
     case vr_shell::ShaderID::LASER_FRAGMENT_SHADER:
       return SHADER(
           varying mediump vec2 v_TexCoordinate;
           uniform sampler2D texture_unit;
           uniform lowp vec4 color;
           uniform mediump float fade_point;
           uniform mediump float fade_end;
 
@@ skipping 283 matching lines @@
 
 VrShellRenderer::VrShellRenderer()
     : textured_quad_renderer_(new TexturedQuadRenderer),
       webvr_renderer_(new WebVrRenderer),
       reticle_renderer_(new ReticleRenderer),
       laser_renderer_(new LaserRenderer) {}
 
 VrShellRenderer::~VrShellRenderer() = default;
 
 }  // namespace vr_shell