AppListController refactoring part 1: AppListShower implementation.

testing/buildbot/chromium.memory.fyi.json

Index: testing/buildbot/chromium.memory.fyi.json
diff --git a/testing/buildbot/chromium.memory.fyi.json b/testing/buildbot/chromium.memory.fyi.json
index 74efcbae421da6f52c4cf78392353b4dc76fbdbb..465518f4c89e9e9fc29d341bdb97ea0f50ee695f 100644
--- a/testing/buildbot/chromium.memory.fyi.json
+++ b/testing/buildbot/chromium.memory.fyi.json
@@ -88,6 +88,9 @@
         "test": "app_list_unittests"
       },
       {
+        "test": "app_list_shower_unittests"
+      },
+      {
         "test": "display_unittests"
       },
       {
@@ -205,6 +208,7 @@
   "Chromium OS Builder (valgrind)": {
     "additional_compile_targets": [
       "app_list_unittests",
+      "app_list_shower_unittests",
       "ash_unittests",
       "aura_unittests",
       "base_unittests",
@@ -243,6 +247,7 @@
       "accessibility_unittests",
       "angle_unittests",
       "app_list_unittests",
+      "app_list_shower_unittests",
       "aura_unittests",
       "base_unittests",
       "blink_heap_unittests",
@@ -292,6 +297,7 @@
       "accessibility_unittests",
       "angle_unittests",
       "app_list_unittests",
+      "app_list_shower_unittests",
       "aura_unittests",
       "base_unittests",
       "blink_heap_unittests",
@@ -350,6 +356,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "app_list_shower_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "app_list_unittests"
       },
       {
@@ -635,6 +647,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "app_list_shower_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "app_list_unittests"
       },
       {
@@ -937,6 +955,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "app_list_shower_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "app_list_unittests"
       },
       {
@@ -2209,6 +2233,9 @@
         "test": "app_list_unittests"
       },
       {
+        "test": "app_list_shower_unittests"
+      },
+      {
         "test": "aura_unittests"
       },
       {
@@ -2276,6 +2303,9 @@
         "test": "app_list_unittests"
       },
       {
+        "test": "app_list_shower_unittests"
+      },
+      {
         "test": "aura_unittests"
       },
       {
@@ -2415,6 +2445,9 @@
         "test": "app_list_unittests"
       },
       {
+        "test": "app_list_shower_unittests"
+      },
+      {
         "test": "aura_unittests"
       },
       {