Content Indexing fieldtrail config

- Add ContentIndexingDownloadHome fieldtrail Finch config.
- Add ContentIndexingNTP fieldtrail Finch config.

TBR=dtrainor@chromium.org

Bug: 1040170
Change-Id: I571bd1b840b2527080b3e39807cb91bc0e33c021
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1992241Reviewed-by: Hesen Zhang <hesen@chromium.org>
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Commit-Queue: Hesen Zhang <hesen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#729830}

testing/variations/fieldtrial_testing_config.json

@@ -1702,6 +1702,36 @@
             ]
         }
     ],
+    "ContentIndexingDownloadHome": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "ContentIndexingDownloadHome",
+                    "enable_features": [
+                        "ContentIndexingDownloadHome"
+                    ]
+                }
+            ]
+        }
+    ],
+    "ContentIndexingNTP": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "ContentIndexingNTP",
+                    "enable_features": [
+                        "ContentIndexingNTP"
+                    ]
+                }
+            ]
+        }
+    ],
     "ContextMenuSearchWithGoogleLensMultiArm": [
         {
             "platforms": [