Implement chrome.experimental.clipboard extension API.

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 2453 matching lines @@
       {
         "name": "createIncognitoTab",
         "type": "function",
         "description": "Creates an incognito tab during internal testing. Succeeds even if the extension is not enabled in incognito mode.",
         "parameters": [
           {"type": "string", "name": "url"}
         ]
       }
     ],
     "events": []
+  },
+  {
+    "namespace": "experimental.clipboard",
+    "types": [],
+    "functions": [
+      {
+        "name": "executeCopy",
+        "type": "function",
+        "description": "Triggers a copy operation in the specified tab.",
+        "parameters": [
+          {"type": "integer", "name": "tabId", "minimum": 0},
+          {"type": "function", "name": "callback", "optional": true, "parameters": []}
+        ]
+      },
+      {
+        "name": "executeCut",
+        "type": "function",
+        "description": "Triggers a cut operation in the specified tab.",
+        "parameters": [
+          {"type": "integer", "name": "tabId", "minimum": 0},
+          {"type": "function", "name": "callback", "optional": true, "parameters": []}
+        ]
+      },
+      {
+        "name": "executePaste",
+        "type": "function",
+        "description": "Triggers a paste operation in the specified tab.",
+        "parameters": [
+          {"type": "integer", "name": "tabId", "minimum": 0},
+          {"type": "function", "name": "callback", "optional": true, "parameters": []}
+        ]
+      }
+    ],
+    "events": []
   }
 ]