Update WebXR framebufferScale in perf tests

Updates the framebufferScale used by WebXR performance tests to
correspond to the recommended scale and the 1:1 pixel mapping scale.

The implementation was changed recently, but these values were not
updated at the same time, causing the perf tests to render WebXR
scenes at significantly lower resolution than before.

Bug: 853400
Change-Id: I247682ea97ac5910d0195fdba1004698c4c0679b
Reviewed-on: https://chromium-review.googlesource.com/1116190Reviewed-by: Klaus Weidner <klausw@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570846}

tools/perf/contrib/vr_benchmarks/webxr_sample_pages.py

@@ -36,17 +36,17 @@ class WebXrSamplePageSet(VrStorySet):
     # turned off.
     cube_test_cases_no_vsync = [
       # Standard sample app with no changes.
-      ['framebufferScale=0.7'],
-      # Increased render scale.
       ['framebufferScale=1.0'],
+      # Increased render scale.
+      ['framebufferScale=1.4'],
       # Default render scale, increased load.
-      ['framebufferScale=0.7', 'heavyGpu=1', 'cubeScale=0.2', 'workTime=5'],
+      ['framebufferScale=1.0', 'heavyGpu=1', 'cubeScale=0.2', 'workTime=5'],
       # Further increased load.
-      ['framebufferScale=0.7', 'heavyGpu=1', 'cubeScale=0.3', 'workTime=10'],
+      ['framebufferScale=1.0', 'heavyGpu=1', 'cubeScale=0.3', 'workTime=10'],
       # Absurd load for fill-rate testing. Only half the cube sea is rendered,
       # and the page automatically rotates the view between the rendered and
       # unrendered halves.
-      ['frameBufferScale=1.0', 'heavyGpu=1', 'cubeScale=0.4', 'workTime=4',
+      ['frameBufferScale=1.4', 'heavyGpu=1', 'cubeScale=0.4', 'workTime=4',
        'halfOnly=1', 'autorotate=1'],
     ]