[patch]: rename method

* add an ability to get single hunk text for any single hunk patches,
 e.g. deleted, new files changes

platform/vcs-api/vcs-api-core/src/com/intellij/openapi/diff/impl/patch/TextFilePatch.java

@@ -67,7 +67,8 @@ public class TextFilePatch extends FilePatch {
     return myHunks.size() == 1 && myHunks.get(0).isNewContent();
   }
 
-  public String getNewFileText() {
+  public String getSingleHunkPatchText() {
+    assert myHunks.size() == 1;
     return myHunks.get(0).getText();
   }
 

platform/vcs-impl/src/com/intellij/openapi/diff/impl/patch/apply/ApplyTextFilePatch.java

@@ -80,7 +80,7 @@ public class ApplyTextFilePatch extends ApplyFilePatchBase<TextFilePatch> {
         //
       }
     }
-    document.setText(myPatch.getNewFileText());
+    document.setText(myPatch.getSingleHunkPatchText());
     FileDocumentManager.getInstance().saveDocument(document);
   }
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/patch/TextFilePatchInProgress.java

@@ -53,7 +53,7 @@ public class TextFilePatchInProgress extends AbstractFilePatchInProgress<TextFil
       myConflicts = null;
       if (FilePatchStatus.ADDED.equals(myStatus)) {
         final FilePath newFilePath = VcsUtil.getFilePath(myIoCurrentBase, false);
-        final String content = myPatch.getNewFileText();
+        final String content = myPatch.getSingleHunkPatchText();
         myNewContentRevision = new SimpleContentRevision(content, newFilePath, myPatch.getAfterVersionId());
       }
       else {

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/shelf/ShelvedChange.java

@@ -220,7 +220,7 @@ public class ShelvedChange {
 
     private String loadContent(final TextFilePatch patch) throws ApplyPatchException {
       if (patch.isNewFile()) {
-        return patch.getNewFileText();
+        return patch.getSingleHunkPatchText();
       }
       if (patch.isDeletedFile()) {
         return null;