[Benchmarking] Updated the dimension to ensure homogeneous fleets: updating...

[Benchmarking] Updated the dimension to ensure homogeneous fleets: updating device OS for Android Go and Android pixel2

In order to ensure homogeneous fleets, we need to have more specific
dimension values when looking for bots. This set of CLs updated some
existing dimensions, and added the synthetic_product_name values for
dimensions if appropriate.

This CL updated the device_os for the following Android builders. The
available bots under the old/new dimension values can be found in the
links.
 - android-go-perf: https://chrome-swarming.appspot.com/botlist?c=id&c=task&c=device_os&c=device_os_flavor&c=device_type&c=gpu&c=os&c=status&c=synthetic_product_name&d=desc&f=device_os_flavor%3Agoogle&f=device_type%3Agobo&f=device_os%3AO&f=os%3AAndroid&f=pool%3Achrome.tests.perf&s=synthetic_product_name
- android-go_webview-perf: https://chrome-swarming.appspot.com/botlist?c=id&c=task&c=device_os&c=device_os_flavor&c=device_type&c=os&c=pool&c=status&c=synthetic_product_name&d=asc&f=device_os_flavor%3Agoogle&f=device_type%3Agobo&f=device_os%3AO&f=os%3AAndroid&f=pool%3Achrome.tests.perf-webview&s=synthetic_product_name
 - android-pixel2_webview-perf: https://chrome-swarming.appspot.com/botlist?c=id&c=task&c=device_os&c=device_os_flavor&c=device_type&c=os&c=pool&c=status&c=synthetic_product_name&d=desc&f=device_os_flavor%3Agoogle&f=device_type%3Awalleye&f=device_os%3AO&f=os%3AAndroid&f=pool%3Achrome.tests.perf-webview&s=device_type
 - android-pixel2-perf: https://chrome-swarming.appspot.com/botlist?c=id&c=task&c=device_os&c=device_os_flavor&c=device_type&c=os&c=pool&c=status&c=synthetic_product_name&d=desc&f=device_os_flavor%3Agoogle&f=device_type%3Awalleye&f=device_os%3AO&f=os%3AAndroid&f=pool%3Achrome.tests.perf&s=synthetic_product_name

Bug: chromium:996830
Change-Id: I97b40110ff6a0c86ac200f245ebc39c79787a33a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1889948Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Wenbin Zhang <wenbinzhang@google.com>
Cr-Commit-Position: refs/heads/master@{#711010}

testing/buildbot/chromium.perf.json

@@ -881,7 +881,7 @@
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
-              "device_os": "O",
+              "device_os": "OMB1.180119.001",
               "device_os_flavor": "google",
               "device_type": "gobo",
               "os": "Android",
@@ -927,7 +927,7 @@
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
-              "device_os": "O",
+              "device_os": "OMB1.180119.001",
               "device_os_flavor": "google",
               "device_type": "gobo",
               "os": "Android",
@@ -1255,7 +1255,7 @@
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
-              "device_os": "O",
+              "device_os": "OPM1.171019.021",
               "device_os_flavor": "google",
               "device_type": "walleye",
               "os": "Android",
@@ -1301,7 +1301,7 @@
           "can_use_on_swarming_builders": true,
           "dimension_sets": [
             {
-              "device_os": "O",
+              "device_os": "OPM1.171019.021",
               "device_os_flavor": "google",
               "device_type": "walleye",
               "os": "Android",

tools/perf/core/perf_data_generator.py

@@ -346,7 +346,7 @@ BUILDERS = {
     ],
     'platform': 'android-chrome',
     'dimension': {
-      'device_os': 'O',
+      'device_os': 'OMB1.180119.001',
       'device_type': 'gobo',
       'device_os_flavor': 'google',
       'pool': 'chrome.tests.perf',
@@ -368,7 +368,7 @@ BUILDERS = {
       'pool': 'chrome.tests.perf-webview',
       'os': 'Android',
       'device_type': 'gobo',
-      'device_os': 'O',
+      'device_os': 'OMB1.180119.001',
       'device_os_flavor': 'google',
     },
   },
@@ -517,7 +517,7 @@ BUILDERS = {
       'pool': 'chrome.tests.perf-webview',
       'os': 'Android',
       'device_type': 'walleye',
-      'device_os': 'O',
+      'device_os': 'OPM1.171019.021',
       'device_os_flavor': 'google',
     },
   },
@@ -537,7 +537,7 @@ BUILDERS = {
       'pool': 'chrome.tests.perf',
       'os': 'Android',
       'device_type': 'walleye',
-      'device_os': 'O',
+      'device_os': 'OPM1.171019.021',
       'device_os_flavor': 'google',
     },
   },