camera3: Update focalLength tags.

Change-Id: I59614223ae65e602f3461029cb4b8848fb22950e
diff --git a/camera/docs/docs.html b/camera/docs/docs.html
index 9f7883b..3528f5b 100644
--- a/camera/docs/docs.html
+++ b/camera/docs/docs.html
@@ -6780,7 +6780,7 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>Lens optical zoom setting</p>
+              <p>The current lens focal length; used for optical zoom.<wbr/></p>
             </td>
 
             <td class="entry_units">
@@ -6788,7 +6788,7 @@
             </td>
 
             <td class="entry_range">
-              <p>&gt; 0</p>
+              <p><a href="#static_android.lens.info.availableFocalLengths">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Focal<wbr/>Lengths</a></p>
             </td>
 
             <td class="entry_tags">
@@ -6803,7 +6803,15 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/></p>
+              <p>This setting controls the physical focal length of the camera
+device's lens.<wbr/> Changing the focal length changes the field of
+view of the camera device,<wbr/> and is usually used for optical zoom.<wbr/></p>
+<p>Like <a href="#controls_android.lens.focusDistance">android.<wbr/>lens.<wbr/>focus<wbr/>Distance</a> and <a href="#controls_android.lens.aperture">android.<wbr/>lens.<wbr/>aperture</a>,<wbr/> this
+setting won't be applied instantaneously,<wbr/> and it may take several
+frames before the lens can move to the requested focal length.<wbr/>
+While the focal length is still changing,<wbr/> <a href="#dynamic_android.lens.state">android.<wbr/>lens.<wbr/>state</a> will
+be set to MOVING.<wbr/></p>
+<p>This is expected not to be supported on most devices.<wbr/></p>
             </td>
           </tr>
 
@@ -7059,22 +7067,22 @@
                   n
                 </span>
               <span class="entry_type_visibility"> [public]</span>
-                <div class="entry_type_notes">the list of available focal lengths</div>
+                <div class="entry_type_notes">The list of available focal lengths</div>
 
 
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>If fitted with optical zoom,<wbr/> what focal
-lengths are available.<wbr/> If not,<wbr/> the static focal
-length</p>
+              <p>The available focal lengths for this device for use with
+<a href="#controls_android.lens.focalLength">android.<wbr/>lens.<wbr/>focal<wbr/>Length</a>.<wbr/></p>
             </td>
 
             <td class="entry_units">
             </td>
 
             <td class="entry_range">
-              <p>&gt; 0</p>
+              <p>Each value in this list must be &gt; 0.<wbr/> This list must
+contain at least one value.<wbr/></p>
             </td>
 
             <td class="entry_tags">
@@ -7090,8 +7098,10 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>If optical zoom not supported,<wbr/> only one value
-should be reported</p>
+              <p>If optical zoom is not supported,<wbr/> this will only report
+a single value corresponding to the static focal length of the
+device.<wbr/> Otherwise,<wbr/> this will report every focal length supported
+by the device.<wbr/></p>
             </td>
           </tr>
 
@@ -7671,7 +7681,7 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>Lens optical zoom setting</p>
+              <p>The current lens focal length; used for optical zoom.<wbr/></p>
             </td>
 
             <td class="entry_units">
@@ -7679,7 +7689,7 @@
             </td>
 
             <td class="entry_range">
-              <p>&gt; 0</p>
+              <p><a href="#static_android.lens.info.availableFocalLengths">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Focal<wbr/>Lengths</a></p>
             </td>
 
             <td class="entry_tags">
@@ -7694,7 +7704,15 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/></p>
+              <p>This setting controls the physical focal length of the camera
+device's lens.<wbr/> Changing the focal length changes the field of
+view of the camera device,<wbr/> and is usually used for optical zoom.<wbr/></p>
+<p>Like <a href="#controls_android.lens.focusDistance">android.<wbr/>lens.<wbr/>focus<wbr/>Distance</a> and <a href="#controls_android.lens.aperture">android.<wbr/>lens.<wbr/>aperture</a>,<wbr/> this
+setting won't be applied instantaneously,<wbr/> and it may take several
+frames before the lens can move to the requested focal length.<wbr/>
+While the focal length is still changing,<wbr/> <a href="#dynamic_android.lens.state">android.<wbr/>lens.<wbr/>state</a> will
+be set to MOVING.<wbr/></p>
+<p>This is expected not to be supported on most devices.<wbr/></p>
             </td>
           </tr>
 
diff --git a/camera/docs/metadata_properties.xml b/camera/docs/metadata_properties.xml
index 30cbfbf..f435b69 100644
--- a/camera/docs/metadata_properties.xml
+++ b/camera/docs/metadata_properties.xml
@@ -1656,10 +1656,24 @@
           <tag id="V1" />
         </entry>
         <entry name="focalLength" type="float" visibility="public">
-          <description>Lens optical zoom setting</description>
+          <description>
+          The current lens focal length; used for optical zoom.
+          </description>
           <units>focal length in mm</units>
-          <range>&amp;gt; 0</range>
-          <details>Will not be supported on most devices.</details>
+          <range>android.lens.info.availableFocalLengths</range>
+          <details>
+          This setting controls the physical focal length of the camera
+          device's lens. Changing the focal length changes the field of
+          view of the camera device, and is usually used for optical zoom.
+
+          Like android.lens.focusDistance and android.lens.aperture, this
+          setting won't be applied instantaneously, and it may take several
+          frames before the lens can move to the requested focal length.
+          While the focal length is still changing, android.lens.state will
+          be set to MOVING.
+
+          This is expected not to be supported on most devices.
+          </details>
           <tag id="V1" />
         </entry>
         <entry name="focusDistance" type="float" visibility="public">
@@ -1717,17 +1731,25 @@
             <tag id="V1" />
           </entry>
           <entry name="availableFocalLengths" type="float" visibility="public"
-          type_notes="the list of available focal lengths"
+          type_notes="The list of available focal lengths"
           container="array">
             <array>
               <size>n</size>
             </array>
-            <description>If fitted with optical zoom, what focal
-            lengths are available. If not, the static focal
-            length</description>
-            <range>&amp;gt; 0</range>
-            <details>If optical zoom not supported, only one value
-            should be reported</details>
+            <description>
+            The available focal lengths for this device for use with
+            android.lens.focalLength.
+            </description>
+            <range>
+            Each value in this list must be &amp;gt; 0. This list must
+            contain at least one value.
+            </range>
+            <details>
+            If optical zoom is not supported, this will only report
+            a single value corresponding to the static focal length of the
+            device. Otherwise, this will report every focal length supported
+            by the device.
+            </details>
             <tag id="BC" />
             <tag id="V1" />
           </entry>