[debug-wrapper] Migrate suspended generator scope test

Unfortunately, there's currently no satisfying way of accessing scopes
of suspended generator objects through inspector. This CL implements
access to such scopes through runtime functions instead.

BUG=v8:5530

Review-Url: https://codereview.chromium.org/2513343004
Cr-Commit-Position: refs/heads/master@{#41179}

test/debugger/test-api.js

@@ -292,6 +292,50 @@ class DebugWrapper {
     this.takeReplyChecked(msgid);
   }
 
+  generatorScopeCount(gen) {
+    return %GetGeneratorScopeCount(gen);
+  }
+
+  generatorScope(gen, index) {
+    // These indexes correspond definitions in debug-scopes.h.
+    const kScopeDetailsTypeIndex = 0;
+    const kScopeDetailsObjectIndex = 1;
+
+    const details = %GetGeneratorScopeDetails(gen, index);
+
+    function scopeObjectProperties() {
+      const obj = details[kScopeDetailsObjectIndex];
+      return Object.keys(obj).map((k, v) => v);
+    }
+
+    function setScopeVariableValue(name, value) {
+      const res = %SetScopeVariableValue(gen, null, null, index, name, value);
+      if (!res) throw new Error("Failed to set variable value");
+    }
+
+    const scopeObject =
+        { value : () => details[kScopeDetailsObjectIndex],
+          property : (prop) => details[kScopeDetailsObjectIndex][prop],
+          properties : scopeObjectProperties,
+          propertyNames : () => Object.keys(details[kScopeDetailsObjectIndex])
+              .map((key, _) => key),
+        };
+    return { scopeType : () => details[kScopeDetailsTypeIndex],
+             scopeIndex : () => index,
+             scopeObject : () => scopeObject,
+             setVariableValue : setScopeVariableValue,
+           }
+  }
+
+  generatorScopes(gen) {
+    const count = %GetGeneratorScopeCount(gen);
+    const scopes = [];
+    for (let i = 0; i < count; i++) {
+      scopes.push(this.generatorScope(gen, i));
+    }
+    return scopes;
+  }
+
   get LiveEdit() {
     const debugContext = %GetDebugContext();
     return debugContext.Debug.LiveEdit;