Fixed specification of Page.captureScreenshot's fromSurface argument.

telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py

Index: telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py
diff --git a/telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py b/telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py
index 3ca06345d8a363309eced59ad65d880e92303474..46352db56b5ace06d5037153b78fd39504da4bd9 100644
--- a/telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py
+++ b/telemetry/telemetry/internal/backends/chrome_inspector/inspector_page.py
@@ -139,11 +139,13 @@ class InspectorPage(object):
   def CaptureScreenshot(self, timeout=60):
     request = {
         'method': 'Page.captureScreenshot',
-        # TODO(rmistry): when Chrome is running in headless mode, this
-        # will need to pass True. Telemetry needs to understand
-        # whether the browser is in headless mode, and pass that
-        # knowledge down to this method.
-        'fromSurface': False
+        'params': {
+            # TODO(rmistry): when Chrome is running in headless mode, this
+            # will need to pass True. Telemetry needs to understand
+            # whether the browser is in headless mode, and pass that
+            # knowledge down to this method.
+            'fromSurface': False
+            }
         }
     # "Google API are missing..." infobar might cause a viewport resize
     # which invalidates screenshot request. See crbug.com/459820.