Add feature for condensed NTP tiles.

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
index 53d8d2f157ed7ee18085ee81ff24fd0925a84183..8546b1c06bdcd46e61180ea880b2b30fbc48353f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java
@@ -76,10 +76,16 @@ public class NewTabPageView
     private static final String PARAM_NTP_TILE_TITLE_LINES = "ntp_tile_title_lines";
 
     /**
-     * The maximum number of tiles to try and fit in a row. On smaller screens, there may not be
-     * enough space to fit all of them.
+     * Experiment parameter for whether to use the condensed tile layout on small screens.
      */
-    private static final int MAX_TILE_COLUMNS = 4;
+    private static final String PARAM_NTP_CONDENSED_TILE_LAYOUT_FOR_SMALL_SCREENS_ENABLED =
+            "ntp_condensed_tile_layout_for_small_screens_enabled";

[Alexei Svitkine (slow), 2017/02/27 15:56:27]

Nit: This param name is awfully long. Can you find a shorter name?

e.g.

condensed_layout_for_small_screens
condensed_layout_for_large_screens

[Michael van Ouwerkerk, 2017/02/27 16:53:57]

Done. We can do without the "ntp" part if you prefer, but the "tile" part helps
distinguish it from a related experiment that we want to control separately.

+
+    /**
+     * Experiment parameter for whether to use the condensed tile layout on large screens.
+     */
+    private static final String PARAM_NTP_CONDENSED_TILE_LAYOUT_FOR_LARGE_SCREENS_ENABLED =
+            "ntp_condensed_tile_layout_for_large_screens_enabled";
 
     private NewTabPageRecyclerView mRecyclerView;
 
@@ -234,6 +240,7 @@ public class NewTabPageView
 
         mTileGridLayout = (TileGridLayout) mNewTabPageLayout.findViewById(R.id.tile_grid_layout);
         mTileGridLayout.setMaxRows(getMaxTileRows(searchProviderHasLogo));
+        mTileGridLayout.setMaxColumns(getMaxTileColumns());
         mTileGroup = new TileGroup(mActivity, mManager, mContextMenuManager, mTileGroupDelegate,
                 /* observer = */ this, offlinePageBridge, getTileTitleLines());
 
@@ -248,7 +255,7 @@ public class NewTabPageView
         mNewTabPageLayout.addOnLayoutChangeListener(this);
         setSearchProviderHasLogo(searchProviderHasLogo);
 
-        mTileGroup.startObserving(getMaxTileRows(searchProviderHasLogo) * MAX_TILE_COLUMNS);
+        mTileGroup.startObserving(getMaxTileRows(searchProviderHasLogo) * getMaxTileColumns());
 
         // Set up snippets
         NewTabPageAdapter newTabPageAdapter = new NewTabPageAdapter(mManager, mNewTabPageLayout,
@@ -805,6 +812,20 @@ public class NewTabPageView
                 ChromeFeatureList.NTP_CONDENSED_LAYOUT, PARAM_NTP_MAX_TILE_ROWS, defaultValue);
     }
 
+    /**
+     * Determines The maximum number of tiles to try and fit in a row. On smaller screens, there
+     * may not be enough space to fit all of them.
+     */
+    private int getMaxTileColumns() {
+        if (!mUiConfig.getCurrentDisplayStyle().isSmall()
+                && ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean(
+                           ChromeFeatureList.NTP_CONDENSED_TILE_LAYOUT,
+                           PARAM_NTP_CONDENSED_TILE_LAYOUT_FOR_LARGE_SCREENS_ENABLED, false)) {
+            return 5;
+        }
+        return 4;
+    }
+
     private static int getTileTitleLines() {
         int defaultValue = 2;
         if (ChromeFeatureList.isEnabled(ChromeFeatureList.NTP_CONDENSED_LAYOUT)) {
@@ -814,6 +835,17 @@ public class NewTabPageView
                 ChromeFeatureList.NTP_CONDENSED_LAYOUT, PARAM_NTP_TILE_TITLE_LINES, defaultValue);
     }
 
+    private boolean shouldUseCondensedTileLayout() {
+        if (mUiConfig.getCurrentDisplayStyle().isSmall()) {
+            return ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean(
+                    ChromeFeatureList.NTP_CONDENSED_TILE_LAYOUT,
+                    PARAM_NTP_CONDENSED_TILE_LAYOUT_FOR_SMALL_SCREENS_ENABLED, false);
+        }
+        return ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean(
+                ChromeFeatureList.NTP_CONDENSED_TILE_LAYOUT,
+                PARAM_NTP_CONDENSED_TILE_LAYOUT_FOR_LARGE_SCREENS_ENABLED, false);

[Alexei Svitkine (slow), 2017/02/27 15:56:27]

Nit: Maybe make a helper function in this file that wraps this where you just
have to pass in param name and boolean?

This way, the calls will be simplified and easier to read.

[Michael van Ouwerkerk, 2017/02/27 16:53:57]

I'm not sure another helper function would help much, as both
shouldUseCondensedTileLayout() and
ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean() are already helper
functions, and not that complex. The shorter param name helps a little though.

+    }
+
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         if (mNewTabPageLayout != null) {
@@ -855,7 +887,8 @@ public class NewTabPageView
 
     @Override
     public void onTileDataChanged() {
-        mTileGroup.renderTileViews(mTileGridLayout, !mLoadHasCompleted);
+        mTileGroup.renderTileViews(
+                mTileGridLayout, !mLoadHasCompleted, shouldUseCondensedTileLayout());
         mSnapshotTileGridChanged = true;
 
         // The page contents are initially hidden; otherwise they'll be drawn centered on the page