IDEA-61700 Add soft wraps support to VCS window

Instructed soft wrap appliance place VCS_DIFF to use the same value as MAIN_EDITOR (results in soft wraps appliance at vcs diff window if necessary)

platform/platform-impl/src/com/intellij/openapi/editor/ex/EditorSettingsExternalizable.java

@@ -151,6 +151,10 @@ public class EditorSettingsExternalizable implements NamedJDOMExternalizable, Ex
     for (String placeName : placeNames) {
       try {
         SoftWrapAppliancePlaces place = SoftWrapAppliancePlaces.valueOf(placeName);
+        if (place == SoftWrapAppliancePlaces.VCS_DIFF) {
+          // Don't keep separate setting for vcs diff window for now and let it share the value for main editor.
+          continue;
+        }
         myPlacesToUseSoftWraps.add(place);
       }
       catch (IllegalArgumentException e) {
@@ -258,7 +262,15 @@ public class EditorSettingsExternalizable implements NamedJDOMExternalizable, Ex
   }
 
   public boolean isUseSoftWraps(@NotNull SoftWrapAppliancePlaces place) {
-    return myPlacesToUseSoftWraps.contains(place);
+    if (myPlacesToUseSoftWraps.contains(place)) {
+      return true;
+    }
+    
+    // For now use soft wraps at vcs diff if they are enabled for the main editors.
+    if (place == SoftWrapAppliancePlaces.VCS_DIFF) {
+      return myPlacesToUseSoftWraps.contains(SoftWrapAppliancePlaces.MAIN_EDITOR);
+    }
+    return false;
   }
 
   public void setUseSoftWraps(boolean use) {

platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/mapping/SoftWrapApplianceManager.java

@@ -65,7 +65,6 @@ public class SoftWrapApplianceManager implements FoldingListener, DocumentListen
 
   private final List<SoftWrapAwareDocumentParsingListener> myListeners = new ArrayList<SoftWrapAwareDocumentParsingListener>();
   private final List<IncrementalCacheUpdateEvent> myCacheUpdateEvents = new ArrayList<IncrementalCacheUpdateEvent>();
-  private final List<SoftWrapApplianceStrategy> myApplianceStrategies = new ArrayList<SoftWrapApplianceStrategy>();
 
   private final ProcessingContext myContext              = new ProcessingContext();
   private final FontTypesStorage  myOffset2fontType      = new FontTypesStorage();
@@ -110,28 +109,12 @@ public class SoftWrapApplianceManager implements FoldingListener, DocumentListen
     myLineWrapPositionStrategy = null;
   }
 
-  /**
-   * Registers given strategy to use within the current manager.
-   *
-   * @param strategy    strategy to use during deciding if soft wraps should be recalculated for particular document region.
-   */
-  public void addApplianceStrategy(@NotNull SoftWrapApplianceStrategy strategy) {
-    myApplianceStrategies.add(strategy);
-  }
-
   @SuppressWarnings({"ForLoopReplaceableByForEach"})
   private void recalculateSoftWraps() {
     if (myVisibleAreaWidth <= 0 || myCacheUpdateEvents.isEmpty()) {
       return;
     }
 
-    // Counter-based loop is preferred to for-each in order to avoid unnecessary performance degradation.
-    for (int i = 0; i < myApplianceStrategies.size(); i++) {
-      if (!myApplianceStrategies.get(i).processSoftWraps()) {
-        return;
-      }
-    }
-
     myLastDocumentStamp = myEditor.getDocument().getModificationStamp();
     // There is a possible case that new dirty regions are encountered during processing, hence, we iterate on regions snapshot here.
     List<IncrementalCacheUpdateEvent> events = new ArrayList<IncrementalCacheUpdateEvent>(myCacheUpdateEvents);