[DevTools] Move 'this' evaluation from ExecutionContext to autocomplete.

third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js b/third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js
index 4edc2a27233dcc7c3ba6d8f3f5f5cf75e64db21e..85a4834693db0d93d77fe9f843133b15c7192d7e 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/RuntimeModel.js
@@ -544,11 +544,6 @@ SDK.ExecutionContext = class extends SDK.SDKObject {
       generatePreview,
       userGesture,
       callback) {
-    if (!expression) {
-      // There is no expression, so the completion should happen against global properties.
-      expression = 'this';
-    }
-
     /**
      * @this {SDK.ExecutionContext}
      * @param {?Protocol.Error} error