[Theme] Adjust default colors (green and red) to be lighter

According to designers and internal spec (https://goo.gl/oRp6PA), some
colors are a shade lighter.

Bug: 850571
Test: Visual
Change-Id: I2c593ed0019c9497873f0f8efa42b592e187d89b
Reviewed-on: https://chromium-review.googlesource.com/1099687
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568306}

chrome/browser/ui/views/harmony/harmony_typography_provider.cc

@@ -74,9 +74,9 @@ SkColor GetHarmonyTextColorForNonStandardNativeTheme(
       color_id = ui::NativeTheme::kColorId_LinkEnabled;
       break;
     case STYLE_RED:
-      return inverted_scheme ? gfx::kGoogleRed300 : gfx::kGoogleRed700;
+      return inverted_scheme ? gfx::kGoogleRed300 : gfx::kGoogleRed600;
     case STYLE_GREEN:
-      return inverted_scheme ? gfx::kGoogleGreen300 : gfx::kGoogleGreen700;
+      return inverted_scheme ? gfx::kGoogleGreen300 : gfx::kGoogleGreen600;
   }
   return theme.GetSystemColor(color_id);
 }

ui/native_theme/common_theme.cc

@@ -352,11 +352,11 @@ SkColor GetAuraColor(NativeTheme::ColorId color_id,
 
     // Alert icon colors
     case NativeTheme::kColorId_AlertSeverityLow:
-      return gfx::kGoogleGreen700;
+      return gfx::kGoogleGreen600;
     case NativeTheme::kColorId_AlertSeverityMedium:
       return gfx::kGoogleYellow700;
     case NativeTheme::kColorId_AlertSeverityHigh:
-      return gfx::kGoogleRed700;
+      return gfx::kGoogleRed600;
 
     case NativeTheme::kColorId_NumColors:
       break;