DevTools: implement hidpi-friendly success/error/warning balls.

Source/devtools/devtools.gyp

Index: Source/devtools/devtools.gyp
diff --git a/Source/devtools/devtools.gyp b/Source/devtools/devtools.gyp
index c55c086b67d29c0d1bf5aad884fe37e1406843fe..2011b2b976bff0ba5529d2804f4beb9ed5e5cc42 100644
--- a/Source/devtools/devtools.gyp
+++ b/Source/devtools/devtools.gyp
@@ -368,7 +368,6 @@
             'front_end/Images/databaseTable.png',
             'front_end/Images/deleteIcon.png',
             'front_end/Images/domain.png',
-            'front_end/Images/errorRedDot.png',
             'front_end/Images/forward.png',
             'front_end/Images/fileSystem.png',
             'front_end/Images/frame.png',
@@ -383,11 +382,8 @@
             'front_end/Images/indexedDBIndex.png',
             'front_end/Images/localStorage.png',
             'front_end/Images/paneAddButtons.png',
-            'front_end/Images/paneBottomGrow.png',
-            'front_end/Images/paneBottomGrowActive.png',
             'front_end/Images/paneElementStateButtons.png',
             'front_end/Images/paneFilterButtons.png',
-            'front_end/Images/paneGrowHandleLine.png',
             'front_end/Images/paneRefreshButtons.png',
             'front_end/Images/paneSettingsButtons.png',
             'front_end/Images/popoverArrows.png',
@@ -406,7 +402,6 @@
             'front_end/Images/resourceJSIcon.png',
             'front_end/Images/resourcePlainIcon.png',
             'front_end/Images/resourcePlainIconSmall.png',
-            'front_end/Images/resourcesSizeGraphIcon.png',
             'front_end/Images/resourcesTimeGraphIcon.png',
             'front_end/Images/searchSmallBlue.png',
             'front_end/Images/searchSmallBrightBlue.png',
@@ -426,13 +421,10 @@
             'front_end/Images/spinnerActiveSelected.gif',
             'front_end/Images/spinnerInactive.gif',
             'front_end/Images/spinnerInactiveSelected.gif',
-            'front_end/Images/splitviewDimple.png',
-            'front_end/Images/splitviewDividerBackground.png',
             'front_end/Images/statusbarButtonGlyphs.png',
             'front_end/Images/statusbarButtonGlyphs2x.png',
             'front_end/Images/statusbarResizerHorizontal.png',
             'front_end/Images/statusbarResizerVertical.png',
-            'front_end/Images/successGreenDot.png',
             'front_end/Images/thumbActiveHoriz.png',
             'front_end/Images/thumbActiveVert.png',
             'front_end/Images/thumbHoriz.png',
@@ -458,7 +450,6 @@
             'front_end/Images/toolbarItemSelected.png',
             'front_end/Images/trackHoriz.png',
             'front_end/Images/trackVert.png',
-            'front_end/Images/warningOrangeDot.png',
         ],
         'devtools_extension_api_files': [
             'front_end/ExtensionAPI.js',