[telemetry] Add support for requesting memory dumps via DevTools API

tools/telemetry/telemetry/internal/backends/browser_backend.py

Index: tools/telemetry/telemetry/internal/backends/browser_backend.py
diff --git a/tools/telemetry/telemetry/internal/backends/browser_backend.py b/tools/telemetry/telemetry/internal/backends/browser_backend.py
index 4c3423ec3ffd3551e612e6445efedbe1dbc8736d..b63b0183e01a7e2267e29e35d551b9ef301283cb 100644
--- a/tools/telemetry/telemetry/internal/backends/browser_backend.py
+++ b/tools/telemetry/telemetry/internal/backends/browser_backend.py
@@ -101,3 +101,10 @@ class BrowserBackend(app_backend.AppBackend):
 
   def GetSystemInfo(self):
     raise NotImplementedError()
+
+  @property
+  def supports_memory_dumping(self):
+    return False
+
+  def DumpMemory(self, timeout=web_contents.DEFAULT_WEB_CONTENTS_TIMEOUT):
+    raise NotImplementedError()