Doc: Minor fixes following launch of Performance section on DAC.

Fixes the metaDescription, which had contained dummy text. Change pushed ahead as hotfix.
Also fixes a couple of image URLs, which hadn't reflected the move to under topic/

Change-Id: I9fd776f409934cd5d02e5abba8289f7a79d2ed22
diff --git a/docs/html/topic/performance/index.jd b/docs/html/topic/performance/index.jd
index 08c610f..e08db15 100644
--- a/docs/html/topic/performance/index.jd
+++ b/docs/html/topic/performance/index.jd
@@ -1,6 +1,6 @@
 page.title=Performance
 page.article=true
-page.metaDescription=Android Performance does nice things. Details to come.
+page.metaDescription=Improve your app's performance by learning how to optimize power consumption, launch times, and other important areas of performance.
 
 meta.tags="performance"
 page.tags="performance"
diff --git a/docs/html/topic/performance/launch-time.jd b/docs/html/topic/performance/launch-time.jd
index c9ce1d5..84d5fab 100644
--- a/docs/html/topic/performance/launch-time.jd
+++ b/docs/html/topic/performance/launch-time.jd
@@ -112,7 +112,7 @@
 </p>
 <br/>
 
-  <img src="{@docRoot}performance/images/cold-launch.png">
+  <img src="{@docRoot}topic/performance/images/cold-launch.png">
   <p class="img-caption">
     <strong>Figure 1.</strong> A visual representation of the important parts of
     a cold application launch.
@@ -262,7 +262,7 @@
 </p>
 <br/>
 
-  <img src="{@docRoot}performance/images/displayed-logcat.png">
+  <img src="{@docRoot}topic/performance/images/displayed-logcat.png">
   <p class="img-caption">
     <strong>Figure 2.</strong> Disabling filters, and
     finding the {@code Displayed} value in logcat.